Packet data unit (pdu) structure for supporting distributed relay control protocol (drcp)

ABSTRACT

A method supporting distributed resilient network interconnect (DRNI) in a link aggregation group at a network device is disclosed. The method starts with encapsulating a distributed relay control protocol data unit (DRCPDU) in a frame, wherein the DRCPDU includes a protocol data unit (PDU) structure. The PDU structure includes a type field indicating that the DRCPDU is for DRCP, a version field indicating a version number of the DRCP, and a set of type/length/values (TLVs) including: a terminator TLV indicating an end of the PDU structure, a portal information TLV indicating characteristics of the first portal, a portal configuration information TLV indicating configuration information of the first portal, a DRCP state TLV indicating variables associated with an intra-portal link (IPP), a home ports information TLV and a neighbor ports information TLV. The method continues with transmitting the frame encapsulating the DRCPDU from the network device to a neighbor network device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/294,870,filed Mar. 6, 2019, which is a continuation of application Ser. No.15/339,162, filed Oct. 31, 2016 (now U.S. Pat. No. 10,257,030 issuedApr. 9, 2019), which is a continuation of application Ser. No.14/257,360, filed Apr. 21, 2014 (now U.S. Pat. No. 9,497,074 issued Nov.15, 2016), which are hereby incorporated by reference. This applicationclaims priority to U.S. Provisional Patent Application No. 61/815,204,entitled “Method and System of Implementing Distributed ResilientNetwork Interconnect for a Link Aggregation Group,” filed on Apr. 23,2013, U.S. Provisional Patent Application No. 61/839,022, entitled“Method and System of Implementing Intra-Portal Link of DistributedResilient Network Interconnect for a Link Aggregation Group,” filed onJun. 25, 2013, U.S. Provisional Patent Application No. 61/865,126,entitled “Method and System of Implementing Distributed ResilientNetwork Interconnect for a Link Aggregation Group,” filed on Aug. 12,2013, and U.S. Provisional Patent Application No. 61/902,518, entitled“Method and System of Implementing Distributed Resilient NetworkInterconnect for a Link Aggregation Group,” filed on Nov. 11, 2013, U.S.Provisional Patent Application No. 61/918,610, entitled “Method andSystem of Implementing Distributed Resilient Network Interconnect for aLink Aggregation Group,” filed on Dec. 19, 2013, U.S. Provisional PatentApplication No. 61/941,977, entitled “Method and System of ImplementingDistributed Resilient Network Interconnect for a Link AggregationGroup,” filed on Feb. 19, 2014, U.S. Provisional Patent Application No.61/953,360, entitled “Method and System of Implementing DistributedResilient Network Interconnect for a Link Aggregation Group,” filed onMar. 14, 2014, which are incorporated by reference herein in theirentirety.

This application relates to U.S. Provisional Patent Application No.61/815,200, entitled “Method and System of ImplementingConversation-Sensitive Collection for A Link Aggregation Group,” filedon Apr. 23, 2013, U.S. Provisional Patent Application No. 61/815,203,entitled “Method and System of Updating Conversation Allocation In LinkAggregation,” filed on Apr. 23, 2013, U.S. Provisional PatentApplication No. 61/865,125, entitled “Method and System of UpdatingConversation Allocation in Link Aggregation,” filed on Aug. 12, 2013,U.S. patent application Ser. No. 14/135,556, entitled “Method and Systemof Updating Conversation Allocation in Link Aggregation,” filed on Dec.19, 2013, U.S. patent application Ser. No. 14/134,966, entitled “Methodand System of Implementing Conversation-Sensitive Collection for a LinkAggregation Group,” filed on Dec. 19, 2013, which are incorporated byreference herein in their entirety.

This application is also related to U.S. patent application Ser. No.14/257,252, entitled “Method And System For Network And Intra-portallink (IPL) Sharing In Distributed Relay Control Protocol (DRCP),”Attorney Docket No. 4906P40985US2, filed on Apr. 21, 2014, U.S. patentapplication Ser. No. 14/257,637, entitled “Method and System forSynchronizing With Neighbor In A Distributed Resilient NetworkInterconnect (DRNI) Link Aggregation Group,” Attorney Docket No.4906P43029US1, filed on Apr. 21, 2014, U.S. patent application Ser. No.14/257,769, entitled “Method and System for Synchronizing With Neighborin a Distributed Resilient Network Interconnect (DRNI) Link AggregationGroup,” Attorney Docket No. 4906P43030US1, filed on Apr. 21, 2014, U.S.patent application Ser. No. 14/257,859, entitled “Method and System forUpdating Distributed Resilient Network Interconnect (DRNI) States,”Attorney Docket No. 4906P43031US1, filed on Apr. 21, 2014, and U.S.patent application Ser. No. 14/257,871, entitled “Method and System forSupporting Distributed Relay Control Protocol (DRCP) Operations UponCommunication Failure,” Attorney Docket No. 4906P43032US1, filed on Apr.21, 2014, which are incorporated by reference herein in their entirety.

FIELD

The embodiments of the present invention generally relate to linkaggregation, and more particularly relate to methods and apparatus forimplementing Distributed Resilient Network Interconnect (DRNI) for aLink Aggregation Group (LAG).

BACKGROUND

As illustrated in FIG. 1A, link aggregation is a network configurationand process used to aggregate multiple links between a pair of nodes120, 122 in the network to enable transmission of user data on each ofthe links participating in a Link Aggregation Group (LAG) 101 (see,e.g., Institute of Electrical and Electronics Engineers (IEEE) standard802.1AX). Aggregating multiple network connections in this fashion canincrease throughput beyond what a single connection can sustain, and/orcan be used to provide resiliency in case of a failure of one of thelinks. The “Distributed Resilient Network Interconnect” (DRNI) 102 (seeClause 8 of IEEE P802.1AX-REV™/D1.0, entitled “Draft Standard for Localand Metropolitan Area Networks—Link Aggregation,” dated Feb. 1, 2013,which is incorporated by reference in its entirety within) specifiesextensions to link aggregation in order to be able to use linkaggregation on a network interface even between more than two nodes, forexample between four nodes K, L, M and O as illustrated in FIG. 1B.

As shown in FIG. 1B, a LAG is formed between Network 150 and Network152. More specifically, a LAG is formed between LAG virtual nodes or“portals” 112, 114. The first LAG virtual node or portal 112 includes afirst node (K) and a second node (L). The second LAG virtual node orportal 114 includes a third node (M) and a fourth node (O). These nodescan also be referred to as “Portal Systems”. Note that both the firstand second LAG virtual nodes or portals 112, 114 may include a single ormore than two nodes in a portal. LAG Nodes K and M are connected as peernodes, and LAG Nodes L and O are also connected as peer nodes. As usedin this application, a “LAG virtual node” refers to a DRNI portal in theIEEE documentation discussed above (i.e., two or more nodes that appearas a single node to their respective peers). Additionally, the statementthat virtual node or portal 112 “includes” two nodes K, L means that thevirtual node or portal 112 is emulated by the nodes K, L, this can bereferred to as an “emulated system.” Similarly, the statement thatvirtual node or portal 114 “includes” two nodes M, O means that thevirtual node or portal 114 is emulated by the nodes M, O. Note that linkaggregation group 161 is also formed between K-M and L-O links.

Multiple nodes participating in the LAG appear to be the same virtualnode or portal with a single System ID to their peering partner in theLAG. The System ID is used to identify each node (e.g., node K, node L,node M, and node O). The System ID is included in Link AggregationControl Protocol Data Units (LACPDUs) sent between the individualpartner nodes of the LAG (e.g., between K and M or between L and O). TheSystem ID can be generated based on identifiers of the constituent nodesof a portal using any individual identifier or any combination thereof.A common and unique System ID for the corresponding LAG virtual node orportal can be consistently generated. Thus, as shown in FIG. 1B, node Kand node L belong to the same Network 150 and they are part of the sameDRNI Portal 112 (i.e., the same LAG virtual node), and use a commonSystem ID of “K” for the emulated LAG virtual node 112?. Similarly,Nodes M and O of Network 152 are seen as a single LAG virtual node orportal 114 with a System ID “M” by Nodes K and L.

FIG. 1B also shows a DRNI link allocation of a particular service (seebold link between K and M in FIG. 1B). The allocated link is the workinglink between two working nodes K and M for the particular service, whilethe unallocated link may be provisioned as the protection link betweentwo protection nodes L and O. The service allocation of an interface mayinvolve a Virtual Local Area Network (VLAN), and an identifier for theservice may be a VLAN Identifier (VID), such as a Service VID (i.e.,“S-VID”) (typically identifying services on Network to NetworkInterfaces (NNIs)) or a Customer VID (i.e. “C-VID”) (typicallyidentifying services on User to Network Interfaces (UNIs)). (Note thatbackbone-VIDs are indistinguishable from S-VIDs as they have the sameEthertype.) In the example of FIG. 1B, the service is allocated to theupper link (between upper nodes K, M). The upper link is thus chosen asthe “working” link and the lower link (between nodes L, O) is the“standby” link or “protection” link. Service link allocation, i.e. usingthe same physical link for frame transmission both in the forward and inthe backward directions is highly desirable.

While FIG. 1B shows DRNI portals 112 and 114 each contain two nodes,DRNI portals are not so limited. Each portal may contain one to threenodes. FIG. 1C illustrates a DRNI in an alternate embodiment. Referringto FIG. 1C, link aggregation group 131 contains portal 142 (one networkdevice 130) at one end, and portal 144 (two network devices 132 and 134)at the other end. Also note that FIG. 1C shows a DRNI link allocation ofa particular service (see bold link between network devices 130 and134). The allocated link is the working link between two working nodes(network devices 130 and 134) for the particular service, while theunallocated link may be provisioned as the protection link between twoprotection nodes (network devices 130 and 132). The working node is asingle node in this configuration, but it may contain different sets ofaggregation ports for connecting the working and protection linksbetween the portals 142 and 144.

Service providers utilize various embodiments of link aggregation groups(such as illustrated in FIGS. 1A-C and other alternate DRNI systems) toprovide services to end-users. How to provide services, particularlythrough a DRNI system, is a challenge.

SUMMARY

A method supporting a distributed resilient network interconnect (DRNI)in a link aggregation group at a network device is disclosed. Thenetwork device and a neighbor network device are included in a firstportal of the link aggregation group, wherein the first portal iscoupled via links of the link aggregation group with a second portalincluding one or more remote network devices, wherein the network deviceis communicatively coupled to the neighbor network device via anintra-portal port (IPP) using an intra-portal link (IPL). The methodstarts with encapsulating a distributed relay control protocol data unit(DRCPDU) in a frame, wherein the DRCPDU includes a PDU structure,wherein the PDU structure includes a type field indicating that theDRCPDU is for DRCP, a version field indicating a version number of theDRCP, and a set of type/length/values (TLVs) including: a terminator TLVindicating an end of the PDU structure, a portal information TLVindicating characteristics of the first portal, a portal configurationinformation TLV indicating configuration information of the firstportal, a DRCP state TLV indicating variables associated with the IPP, ahome ports information TLV indicating a current status of the networkdevice in association with the DRNI, and a neighbor ports informationTLV indicating a current status of the neighbor network device inassociation with the DRNI. The method continues with transmitting theframe encapsulating the DRCPDU from the network device to the neighbornetwork device via the IPP.

A network device supporting a distributed resilient network interconnect(DRNI) in a link aggregation group is disclosed. The network device anda neighbor network device are included in a first portal of the linkaggregation group, wherein the first portal is coupled via links of thelink aggregation group with a second portal including one or more remotenetwork devices, wherein the network device is communicatively coupledto the neighbor network device via an intra-portal port (IPP) using anintra-portal link (IPL). The network device comprises ports coupled tothe physical or aggregation link of the link aggregation group and anetwork processor coupled to the ports. The network processor executes aDRNI function, where the DRNI function is operative to causeencapsulation of a distributed relay control protocol data unit (DRCPDU)in a frame, and further operative to cause transmission the frameencapsulating the DRCPDU from the network device to the neighbor networkdevice via the IPP. The PDU structure includes a type field indicatingthat the DRCPDU is for DRCP, a version field indicating a version numberof the DRCP, and a set of type/length/values (TLVs) including: aterminator TLV indicating an end of the PDU structure, a portalinformation TLV indicating characteristics of the first portal, a portalconfiguration information TLV indicating configuration information ofthe first portal, a DRCP state TLV indicating variables associated withthe IPP, a home ports information TLV indicating a current status of thenetwork device in association with the DRNI, and a neighbor portsinformation TLV indicating a current status of the neighbor networkdevice in association with the DRNI.

A non-transitory machine-readable storage medium is disclosed, which hasinstructions stored therein, which when executed by a processor, causethe processor to perform operations at a network device to support adistributed resilient network interconnect (DRNI) in a link aggregationgroup. The network device and a neighbor network device are included ina first portal of the link aggregation group, wherein the first portalis coupled via links of the link aggregation group with a second portalincluding one or more remote network devices, wherein the network deviceis communicatively coupled to the neighbor network device via anintra-portal port (IPP) using an intra-portal link (IPL). The operationsinclude encapsulating a distributed relay control protocol data unit(DRCPDU) in a frame, wherein the DRCPDU includes a PDU structure,wherein the PDU structure includes a type field indicating that theDRCPDU is for DRCP, a version field indicating a version number of theDRCP, and a set of type/length/values (TLVs) including: a terminator TLVindicating an end of the PDU structure, a portal information TLVindicating characteristics of the first portal, a portal configurationinformation TLV indicating configuration information of the firstportal, a DRCP state TLV indicating variables associated with the IPP, ahome ports information TLV indicating a current status of the networkdevice in association with the DRNI, and a neighbor ports informationTLV indicating a current status of the neighbor network device inassociation with the DRNI. The operations continues with transmittingthe frame encapsulating the DRCPDU from the network device to theneighbor network device via the IPP.

Through embodiments of the invention, a DRCP node (e.g., a networkdevice) exchanges information with its neighbor node and thusestablishes and enables DRCP operations of the portal. Thus embodimentsof the invention provide efficient ways for the node to exchangeinformation with its neighboring node.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdescription and accompanying drawings that are used to illustrateembodiments of the invention. In the drawings:

FIG. 1A is a diagram of one embodiment of a Link Aggregation Groupbetween two network devices.

FIG. 1B is a diagram of one embodiment of two Portals connecting twonetworks via a Link Aggregation Group.

FIG. 1C is a diagram of another embodiment of two Portals connecting twonetworks via a Link Aggregation Group.

FIG. 2 is a diagram of one embodiment of a Link Aggregation Sublayer.

FIG. 3A is a diagram of one embodiment of a basic distributed relaysystem.

FIG. 3B is a diagram of one embodiment of an emulated system createdfrom two portal systems.

FIG. 4 is a diagram of one embodiment of two DR functions of adistributed relay.

FIG. 5 is a diagram of DRCPDU data structure.

FIG. 6A is a diagram of Distributed Relay Control Protocol (DRCP) state.

FIG. 6B is a diagram of one embodiment of DRCP.

FIG. 6C is a topology state field of a DRCPDU structure according to oneembodiment of the invention.

FIG. 7 is a flowchart illustrating relationships among state machines.

FIG. 8 is a flowchart illustrating a state machine for a receivemachine.

FIG. 9 is a flowchart illustrating a state machine for periodictransmission.

FIG. 10 is a flowchart illustrating a portal system machine.

FIGS. 11A-B are flowcharts illustrating DRNI and Aggregator machineoperations. FIG. 11A illustrates the DRNI gateway process and FIG. 11Billustrates the DRNI port update process.

FIGS. 12A-B are flowcharts illustrating DRNI IPP machine status. FIG.12A illustrates a state machine to update IPP gateway conversationaccording to one embodiment of the invention and FIG. 12B illustrates astate machine to update IPP port conversation according to oneembodiment of the invention.

FIG. 13 is a diagram of one embodiment of a network device implementingDRNI.

FIG. 14 is another diagram of DRCPDU data structure according to oneembodiment of the invention.

FIG. 15 is another flowchart illustrating relationships among statemachines according to one embodiment of the invention.

FIG. 16 is another flowchart illustrating a state machine for a receivemachine according to one embodiment of the invention.

FIG. 17 is another flowchart illustrating a state machine for periodictransmission according to one embodiment of the invention.

FIG. 18 is another flowchart illustrating a portal system machineaccording to one embodiment of the invention.

FIG. 19 is a flowchart illustrating a DRCP node's operations upon losingcommunication with its neighbor node according to one embodiment of theinvention.

FIG. 20 is a flowchart illustrating a DRCP node's operation incoordinating with its neighbor node upon receiving multiple trafficstreams according to one embodiment of the invention.

FIG. 21 is a diagram of portal topology according to one embodiment ofthe invention.

FIG. 22 is a diagram of an aggregator port reception state machineaccording to one embodiment of the invention.

FIG. 23 is a diagram of a gateway distribution state machine accordingto one embodiment of the invention.

FIG. 24 is a diagram of an IPP N reception state machine according toone embodiment of the invention.

FIG. 25 is another diagram of DRCPDU data structure according to oneembodiment of the invention.

FIG. 26A illustrates a conversation mask TLV for an aggregation portaccording to one embodiment of the invention.

FIG. 26B illustrates a conversation mask state field within aconversation mask TLV of an aggregation port according to one embodimentof the invention.

FIG. 27 illustrates a DRCP node's operation in coordinating with itsneighbor node upon a communication failure condition to one embodimentof the invention.

FIG. 28 illustrates a DRCP node's operation upon a communication failureaccording to one embodiment of the invention.

FIG. 29 is another topology state field of a DRCPDU structure accordingto one embodiment of the invention.

FIG. 30 illustrates a Network/IPL sharing machine according to oneembodiment of the invention.

FIG. 31 illustrates a method for Network/IPL sharing at a node accordingto an embodiment of the invention.

FIG. 32 illustrates a method of communicating through a frame containingDRCPDU structure according to one embodiment of the invention

FIG. 33 illustrates a method for synchronizing with a neighbor in a nodeof a DRNI link aggregation group according to an embodiment of theinvention.

FIG. 34 illustrates a method for updating operational states of a nodein a distributed resilient network interconnect (DRNI) according to anembodiment of the invention.

FIG. 35 illustrates a method for configuring of a set of conversationIDs for aggregator or gateway at a DRCP node in a distributed resilientnetwork interconnect (DRNI) according to an embodiment of the invention.

FIG. 36 illustrates a method for configuring of a set of conversationIDs for IPP at a DRCP node in a distributed resilient networkinterconnect (DRNI) according to an embodiment of the invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the invention may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail inorder not to obscure the understanding of this description.

It will be appreciated, however, by one skilled in the art that theinvention may be practiced without such specific details. In otherinstances, control structures, gate level circuits and full softwareinstruction sequences have not been shown in detail in order not toobscure the invention. Those of ordinary skill in the art, with theincluded descriptions, will be able to implement appropriatefunctionality without undue experimentation.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Terms

The following terms may be used in the description.

Actor: The local entity (i.e., node or network device) in a LinkAggregation Control Protocol (LACP) exchange.

Aggregation Key: A parameter associated with each Aggregation Port andwith each Aggregator of an Aggregation System identifying thoseAggregation Ports that can be aggregated together. Aggregation Ports inan Aggregation System that share the same Aggregation Key value arepotentially able to aggregate together.

Aggregation Port: A Service Access Point (SAP) in an Aggregation Systemthat is supported by an Aggregator.

Aggregation System: A uniquely identifiable entity comprising (amongother things) an arbitrary grouping of one or more aggregation ports forthe purpose of aggregation. An instance of an aggregated link alwaysoccurs between two aggregation systems. A physical device may comprise asignal aggregation system or more than one aggregation system.

Aggregation Client: The layered entity immediately above the LinkAggregation Sublayer, for which the Link Aggregation Sublayer providesan instance of the Internal Sublayer Services (ISS).

Conversation: A set of frames transmitted from one end station toanother, where all the frames form an ordered sequence, and where thecommunicating end stations require the ordering to be maintained amongthe set of frames exchanged.

Conversation ID: An identifier using values (for example, in the rangeof 0 4095) to identify conversations.

Data Terminal Equipment (DTE): Any source or destination of dataconnected to the local area network.

Distributed Relay (DR): A functional entity, distributed over a Portalby a DR Function in each of the Aggregation Systems comprising a Portal,which distributes outgoing frames from Gateways to Aggregators, anddistributes incoming frames from Aggregators to Gateways.

Distributed Resilient Network Interconnect (DRNI): Link Aggregationexpanded to include each of a Portal and an Aggregation System, or two(or more) Portals.

DR Function: The part of a Distributed Relay residing within a singlePortal System.

Gateway: A connection, typically virtual (not a physical link betweensystems) connecting a Distributed Relay to a System, consisting of aGateway Link and two Gateway Ports.

Gateway Conversation ID: The Conversation ID value which is used toselect frames passing through a Gateway. Gateway Conversation ID: TheConversation ID value which is used to select frames passing through aGateway.

Internal Sublayer Service (ISS): An augmented version of the MACservice, defined in IEEE Std 802.1AC-2012.

Intra-Portal Link (IPL): A link used to connect the DR Functionscomprising a Distributed Relay.

Link Aggregation Group (LAG): A group of links that appear to anAggregator Client as if they were a single link. A Link AggregationGroup can connect two Aggregation Systems, an Aggregation System and aPortal, or two Portals. One or more conversations may be associated witheach link that is part of a Link Aggregation Group.

Partner: The remote entity (i.e., node or network device) in a LinkAggregation Control Protocol exchange.

Port conversation identifier (ID): A conversation identifier value thatis used to select frames passing through an Aggregation Port.

Portal: One end of a DRNI; including one or more Aggregation Systems,each with physical links that together comprise a Link AggregationGroup. The Portal's Aggregation Systems cooperate to emulate thepresence of a single Aggregation System to which the entire LinkAggregation Group is attached.

Portal System Number: An integer (for example, from 1 through 3,inclusive) uniquely identifying a Portal System within its Portal.

Selection algorithm: The algorithm used to assign frames to ConversationIDs and Conversation IDs to Aggregation Ports and Gateways.

Service ID: A value extracted from a frame's header (VID, I-SID, etc.)that identifies the service instance with which that frame isassociated.

Service instance: A service instance is a set of Service Access Points(SAPs) such that a Data.Request primitive presented to one SAP canresult in a Data.Indication primitive occurring at one or more of theother SAPs in that set. In the context of operators and customers, aparticular customer is given access to all of the SAPs of such a set bythe operator

Type/Length/Value (TLV): A short, variable length encoding of aninformation element consisting of sequential type, length, and valuefields where the type field identifies the type of information, thelength field indicates the length of the information field in octets,and the value field contains the information itself. The type value islocally defined and needs to be unique within the protocol defined inthis standard.

In the following description and claims, the terms “coupled” and“connected,” along with their derivatives, may be used. It should beunderstood that these terms are not intended as synonyms for each other.“Coupled” is used to indicate that two or more elements, which may ormay not be in direct physical or electrical contact with each other,co-operate or interact with each other. “Connected” is used to indicatethe establishment of communication between two or more elements that arecoupled with each other. A “set,” as used herein refers to any positivewhole number of items including one item.

An electronic device (e.g., an end station, a network device) stores andtransmits (internally and/or with other electronic devices over anetwork) code (composed of software instructions, e.g. a computerprogram comprising instructions) and data using machine-readable media,such as non-transitory machine-readable media (e.g., machine-readablestorage media such as magnetic disks; optical disks; read only memory;flash memory devices; phase change memory) and transitorymachine-readable transmission media (e.g., electrical, optical,acoustical or other form of propagated signals—such as carrier waves,infrared signals). In addition, such electronic devices includehardware, such as a set of one or more processors coupled to one or moreother components—e.g., one or more non-transitory machine-readablestorage media (to store code and/or data) and network connections (totransmit code and/or data using propagating signals), as well as userinput/output devices (e.g., a keyboard, a touchscreen, and/or a display)in some cases. The coupling of the set of processors and othercomponents is typically through one or more interconnects within theelectronic devices (e.g., busses and possibly bridges). Thus, anon-transitory machine-readable medium of a given electronic devicetypically stores instructions for execution on one or more processors ofthat electronic device. One or more parts of an embodiment of theinvention may be implemented using different combinations of software,firmware, and/or hardware.

As used herein, a network device (e.g., a router, switch, bridge) is apiece of networking equipment, including hardware and software, whichcommunicatively interconnects other equipment on the network (e.g.,other network devices, end stations). Some network devices are “multipleservices network devices” that provide support for multiple networkingfunctions (e.g., routing, bridging, switching, Layer 2 aggregation,session border control, Quality of Service, and/or subscribermanagement), and/or provide support for multiple application services(e.g., data, voice, and video). Subscriber end stations (e.g., servers,workstations, laptops, netbooks, palm tops, mobile phones, smartphones,multimedia phones, Voice Over Internet Protocol (VOIP) phones, userequipment, terminals, portable media players, GPS units, gaming systems,set-top boxes) access content/services provided over the Internet and/orcontent/services provided on virtual private networks (VPNs) overlaid on(e.g., tunneled through) the Internet. The content and/or services aretypically provided by one or more end stations (e.g., server endstations) belonging to a service or content provider or end stationsparticipating in a peer-to-peer (P2P) service, and may include, forexample, public webpages (e.g., free content, store fronts, searchservices), private webpages (e.g., username/password accessed webpagesproviding email services), and/or corporate networks over VPNs.Typically, subscriber end stations are coupled (e.g., through customerpremise equipment coupled to an access network (wired or wirelessly)) toedge network devices, which are coupled (e.g., through one or more corenetwork devices) to other edge network devices, which are coupled toother end stations (e.g., server end stations).

Network devices are commonly separated into a control plane and a dataplane (sometimes referred to as a forwarding plane or a media plane). Inthe case that the network device is a router (or is implementing routingfunctionality), the control plane typically determines how data (e.g.,packets) is to be routed (e.g., the next hop for the data and theoutgoing port for that data), and the data plane is in charge offorwarding that data. For example, the control plane typically includesone or more routing protocols (e.g., an exterior gateway protocol suchas Border Gateway Protocol (BGP) (RFC 4271), Interior GatewayProtocol(s) (IGP) (e.g., Open Shortest Path First (OSPF) (RFC 2328 and5340), Intermediate System to Intermediate System (IS-IS) (RFC 1142),Routing Information Protocol (RIP) (version 1 RFC 1058, version 2 RFC2453, and next generation RFC 2080)), Label Distribution Protocol (LDP)(RFC 5036), Resource Reservation Protocol (RSVP) (RFC 2205, 2210, 2211,2212, as well as RSVP-Traffic Engineering (TE): Extensions to RSVP forLSP Tunnels RFC 3209, Generalized Multi-Protocol Label Switching (GMPLS)Signaling RSVP-TE RFC 3473, RFC 3936, 4495, and 4558)) that communicatewith other network devices to exchange routes and select those routesbased on one or more routing metrics. In addition, the control planealso typically include ISO layer 2 control protocols such as RapidSpanning Tree Protocol (RSTP), Multiple Spanning Tree Protocol (MSTP),and SPB (Shortest Path Bridging), which have been standardized byvarious standard bodies (e.g., SPB has been defined in IEEE Std802.1aq-2012).

Routes and adjacencies are stored in one or more routing structures(e.g., Routing Information Base (RIB), Label Information Base (LIB), oneor more adjacency structures) on the control plane. The control planeprograms the data plane with information (e.g., adjacency and routeinformation) based on the routing structure(s). For example, the controlplane programs the adjacency and route information into one or moreforwarding structures (e.g., Forwarding Information Base (FIB), LabelForwarding Information Base (LFIB), and one or more adjacencystructures) on the data plane. The data plane uses these forwarding andadjacency structures when forwarding traffic.

Each of the routing protocols downloads route entries to a main RIBbased on certain route metrics (the metrics can be different fordifferent routing protocols). Each of the routing protocols can storethe route entries, including the route entries which are not downloadedto the main RIB, in a local RIB (e.g., an OSPF local RIB). A RIB modulethat manages the main RIB selects routes from the routes downloaded bythe routing protocols (based on a set of metrics) and downloads thoseselected routes (sometimes referred to as active route entries) to thedata plane. The RIB module can also cause routes to be redistributedbetween routing protocols. For layer 2 forwarding, the network devicecan store one or more bridging tables that are used to forward databased on the layer 2 information in that data.

Typically, a network device includes a set of one or more line cards, aset of one or more control cards, and optionally a set of one or moreservice cards (sometimes referred to as resource cards). These cards arecoupled together through one or more interconnect mechanisms (e.g., afirst full mesh coupling the line cards and a second full mesh couplingall of the cards). The set of line cards make up the data plane, whilethe set of control cards provide the control plane and exchange packetswith external network devices through the line cards. The set of servicecards can provide specialized processing (e.g., Layer 4 to Layer 7services (e.g., firewall, Internet Protocol Security (IPsec) (RFC 4301and 4309), Intrusion Detection System (IDS), peer-to-peer (P2P), Voiceover IP (VoIP) Session Border Controller, Mobile Wireless Gateways(Gateway General Packet Radio Service (GPRS) Support Node (GGSN),Evolved Packet Core (EPC) Gateway)). By way of example, a service cardmay be used to terminate IPsec tunnels and execute the attendantauthentication and encryption algorithms.

As used herein, a node forwards IP packets on the basis of some of theIP header information in the IP packet; where IP header informationincludes source IP address, destination IP address, source port,destination port (where “source port” and “destination port” referherein to protocol ports, as opposed to physical ports of a networkdevice), transport protocol (e.g., user datagram protocol (UDP) (RFC768, 2460, 2675, 4113, and 5405), Transmission Control Protocol (TCP)(RFC 793 and 1180), and differentiated services (DSCP) values (RFC 2474,2475, 2597, 2983, 3086, 3140, 3246, 3247, 3260, 4594, 5865, 3289, 3290,and 3317). Nodes are implemented in network devices. A physical node isimplemented directly on the network device, whereas a virtual node is asoftware, and possibly hardware, abstraction implemented on the networkdevice. Thus, multiple virtual nodes may be implemented on a singlenetwork device.

A network interface may be physical or virtual; and an interface addressis an IP address assigned to a network interface, be it a physicalnetwork interface or virtual network interface. A physical networkinterface is hardware in a network device through which a networkconnection is made (e.g., wirelessly through a wireless networkinterface controller (WNIC) or through plugging in a cable to a portconnected to a network interface controller (NIC)). Typically, a networkdevice has multiple physical network interfaces. A virtual networkinterface may be associated with a physical network interface, withanother virtual interface, or stand on its own (e.g., a loopbackinterface, a point to point protocol interface). A network interface(physical or virtual) may be numbered (a network interface with an IPaddress) or unnumbered (a network interface without an IP address). Aloopback interface (and its loopback address) is a specific type ofvirtual network interface (and IP address) of a node (physical orvirtual) often used for management purposes; where such an IP address isreferred to as the nodal loopback address. The IP address(es) assignedto the network interface(s) of a network device, are referred to as IPaddresses of that network device; at a more granular level, the IPaddress(es) assigned to network interface(s) assigned to a nodeimplemented on a network device, can be referred to as IP addresses ofthat node.

Some network devices provide support for implementing VPNs (VirtualPrivate Networks) (e.g., Layer 2 VPNs and/or Layer 3 VPNs). For example,the network device where a provider's network and a customer's networkare coupled are respectively referred to as PEs (Provider Edge) and CEs(Customer Edge). In a Layer 2 VPN, forwarding typically is performed onthe CE(s) on either end of the VPN and traffic is sent across thenetwork (e.g., through one or more PEs coupled by other networkdevices). Layer 2 circuits are configured between the CEs and PEs (e.g.,an Ethernet port, an ATM permanent virtual circuit (PVC), a Frame RelayPVC). In a Layer 3 VPN, routing typically is performed by the PEs. Byway of example, an edge network device that supports multiple contextsmay be deployed as a PE; and a context may be configured with a VPNprotocol, and thus that context is referred as a VPN context.

Some network devices provide support for VPLS (Virtual Private LANService) (RFC 4761 and 4762). For example, in a VPLS network, subscriberend stations access content/services provided through the VPLS networkby coupling to CEs, which are coupled through PEs coupled by othernetwork devices. VPLS networks can be used for implementing triple playnetwork applications (e.g., data applications (e.g., high-speed Internetaccess), video applications (e.g., television service such as IPTV(Internet Protocol Television), VoD (Video-on-Demand) service), andvoice applications (e.g., VoIP (Voice over Internet Protocol) service)),VPN services, etc. VPLS is a type of layer 2 VPN that can be used formulti-point connectivity. VPLS networks also allow subscriber endstations that are coupled with CEs at separate geographical locations tocommunicate with each other across a Wide Area Network (WAN) as if theywere directly attached to each other in a Local Area Network (LAN)(referred to as an emulated LAN).

In VPLS networks, each CE typically attaches, possibly through an accessnetwork (wired and/or wireless), to a bridge module of a PE via anattachment circuit (e.g., a virtual link or connection between the CEand the PE). The bridge module of the PE attaches to an emulated LANthrough an emulated LAN interface. Each bridge module acts as a “VirtualSwitch Instance” (VSI) by maintaining a forwarding table that maps MACaddresses to pseudowires and attachment circuits. PEs forward frames(received from CEs) to destinations (e.g., other CEs, other PEs) basedon the MAC destination address field included in those frames.

Link Aggregation Sublayer

FIG. 2 is a diagram of one embodiment of Link Aggregation Sublayer 200.Aggregator client 202 communicates with a set of aggregation ports 292,294, 296 through aggregator 250. In one embodiment, aggregator 250presents a standard IEEE Std 802.1Q Internal Sublayer Service (ISS)interface to aggregator client 202. Aggregator 250 binds to one or moreaggregation ports including aggregation Ports 292, 294, 296. Aggregator250 distributes frame transmissions from aggregator client 202 toaggregation Ports 292, 294, 296, and to collect received frames fromaggregation Ports 292, 294, 296 and pass them to aggregator client 202transparently.

The binding of aggregation ports 292, 294, 296 to aggregator 250 ismanaged by link aggregation control 210, which is responsible fordetermining which links can be aggregated, aggregating them, bindingaggregation ports to an appropriate aggregator, and monitoringconditions to determine when a change in aggregation is needed. Suchdetermination and binding can be under manual control through directmanipulation of the state variables of link aggregation (e.g., throughaggregation keys) by a network manager. In addition, automaticdetermination, configuration, binding, and monitoring may occur throughthe use of Link Aggregation Control Protocol (LACP) 214. LACP 214 usespeer exchanges across the links to determine, on an ongoing basis, theaggregation capability of the various links, and continuously providesthe maximum level of aggregation capability achievable between a givenpair of Aggregation Systems.

An Aggregation System can contain multiple aggregators, serving multipleaggregator clients. A given aggregation port will bind to (at most) asingle aggregator at any time. An aggregator client is served by asingle aggregator at a time.

Frame ordering is maintained for certain sequences of frame exchangesbetween aggregator clients (known as conversations). Frame distributor234 ensures that all frames of a given conversation are passed to asingle aggregation port. For a given conversation, frame collector 224is required to pass frames to aggregator client 202 in the order thatthey are received from the aggregation port. Frame collector 224 isotherwise free to select frames received from aggregation ports 292,294, 296 in any order. Since there are no means for frames to bemisordered on a single link, this ensures that frame ordering ismaintained for any conversation. Conversations can be moved amongaggregation ports within a Link Aggregation Group, both for loadbalancing and to maintaining availability in the event of link failures.

Aggregation ports 292, 294, 296 are each assigned media access control(MAC) addresses, which are unique over the Link Aggregation Group and toany bridged local area network (LAN) (e.g., one complying with IEEE802.1Q Bridged LAN) to which the Link Aggregation Group is connected.These MAC addresses are used as the source addresses for frame exchangesthat are initiated by entities within Link Aggregation Sublayer 270itself (i.e., LACP 214 and Marker protocol exchanges).

Aggregator 250 (and other aggregators if deployed) is assigned a MACaddress, unique over the Link Aggregation Group and to bridged LAN(e.g., one complying with IEEE 802.1Q Bridged LAN) to which the LinkAggregation Group is connected. This address is used as the MAC addressof the Link Aggregation Group from the perspective of the aggregatorclient 202, both as a source address for transmitted frames and as thedestination address for received frames. The MAC address of aggregator250 may be one of the MAC addresses of an aggregation port in theassociated Link Aggregation Group.

Distributed Resilient Network Interconnect (DRNI)

Link aggregation creates a Link Aggregation Group that is a collectionof one or more physical links that appears, to higher layers, to be asingle logical link. The Link Aggregation Group has two ends, eachterminating in an Aggregation System. DRNI expands the concept of linkaggregation so that, at either or both ends of a link aggregation group,the single Aggregation System is replaced by a Portal, each composedfrom one or more Aggregation Systems.

DRNI is created by using a distributed relay to interconnect two or moresystems, each running link aggregation, to create a Portal. EachAggregation System in the Portal (i.e., each Portal System) runs linkaggregation with a single aggregator. The distributed relay enables thePortal Systems to jointly terminate a Link Aggregation Group. To allother Aggregation Systems to which the Portal is connected, the LinkAggregation Group appears to terminate in a separate emulatedAggregation System created by the Portal Systems.

The intention is to create DRNI by introducing a Distributed Relay tointerconnect two or three Systems, each running Link Aggregation, tocreate a Portal. Each System in the Portal (i.e., each Portal System)runs Link Aggregation with a single Aggregator. The Distributed Relay isintended to enable the Portal Systems to jointly terminate a LinkAggregation Group. To all other Systems to which the Portal isconnected, the Link Aggregation Group shall appear to terminate in aseparate emulated System created by the Portal Systems. The abovementioned IEEE 802.1AX-REV/D1.0, does not provide sufficient informationwith regards to how the Distributed Relay is to function.

Distributed Relays

DRNI is created by using a Distributed Relay to interconnect two orthree Systems, each running Link Aggregation, to create a Portal. EachSystem in the Portal (i.e., each Portal System) runs Link Aggregationwith a single Aggregator. The Distributed Relay enables the PortalSystems to jointly terminate a Link Aggregation Group. To all otherSystems to which the Portal is connected, the Link Aggregation Groupappears to terminate in a separate emulated System created by the PortalSystems.

FIG. 3A illustrates a basic distributed relay system as the startingpoint for describing the Distributed Relay. The network links depictedin the FIG. 3A and discussed herein correspond to physical or logicallinks that are visible to and are under the control of networkprotocols. In this diagram, Systems A and B each are characterized byperforming a “Function 1,” which is some kind of packet relay function,e.g., a router or a bridge. “Function 1” could also be a file serveroperation, in which case the outside two “ports” on each System wouldlikely not be present. Each system runs a single instance of a LinkAggregation Sublayer. In one embodiment, it is desired that the shadedports be associated into a Portal with a Distributed Relay.

FIG. 3A is an example, not the general case. In general, the DistributedRelay supports:

a) The necessary protocols and procedures for only the configurationslisted herein below are provided by this application.

b) Link Aggregation functions, each subsuming one or more MACs.

c) Connections among the Portal Systems of the Distributed Relay.

The purpose of introducing the Distributed Relay functional layer inthis example is to make these two Portal Systems appear, to the systemsconnected to them, to be in the configuration illustrated in FIG. 3B.There appears to exist a third emulated System C, connected to theoriginal Portal Systems by a link that has been inserted betweenFunction 1 and Link Aggregation. That is, Portal Systems A and Bconspire to behave, insofar as any other Systems to which they areconnected can discern, as if emulated System C actually exists, as shownin FIG. 3B. While FIG. 3B is an example, it illustrates the principlesof the Distributed Relay:

d) The Distributed Relay in the emulated System C is an (N+1)-port relayfor N Portal Systems, with N Gateway Ports connected to the PortalSystems, and a single Emulated Link Aggregation Sublayer associated withthe original Portal Systems.

e) The Aggregation Ports (also referred to herein as MACs) have beenmoved to the emulated System, and thus appear, to all other Systems, tobe equally distant from the real Portal Systems comprising theDistributed Relay.

The actual constructs used by the two Portal Systems to create theemulated System C are illustrated in FIG. 4. FIG. 4 shows the two DRFunctions of the Distributed Relay, one DR Function in each System A andB. This example illustrates the remaining principles of the DistributedRelay:

f) In each System A and B, the ports that are to be associated withSystem C are moved to a position below the DR Function's LinkAggregation Sublayer.

g) A virtual link and its terminating virtual MACs, called a “Gateway,”is constructed to connect each DR Function to its Function 1.

h) Between each pair of DR Functions in the Portal there is constructedan Intra-Portal Link (IPL), terminated at each end by an Intra-PortalPort (IPP). (This can exist in many forms; see discussion herein below)

i) There is a “Gateway algorithm” that decides through which Gateway aframe can pass into or out of the emulated Distributed Relay.

j) Similarly, a “Port algorithm” decides through which Portal System'sAggregation Ports a frame can pass into or out of the emulatedDistributed Relay.

k) As mentioned above, there can be three Systems participating tocreate a Portal and a emulated System C. In that case, the DistributedRelay in emulated System C has an additional Gateway Port, one to eachPortal System, and IPLs to interconnect the DR Functions.

l) The DR Functions, as specified herein below, work together to moveframes between the Gateways, the IPL, and the Link Aggregationsublayers.

Distributed Relay Operation and Procedures

The DR Function in each Portal System (FIG. 4) is intended to have(subject to operational failures) three kinds of ports:

A) Intra-Portal Ports, at most one (perhaps complex in some embodiment)IPL Port connected to each of the other Portal System(s) belonging tothe same Portal;

B) Exactly one virtual Gateway Port with a virtual Link to a virtualGateway Port in the Portal System in which the DR Function resides; and

C) Exactly one Aggregator Port (the port that is supported by the ISSinstance identified by the prefix Agg) to the Link Aggregation sublayerwith any number of Aggregation Ports, intended to connect to othersystems in a manner such that those other Systems believe they areconnected to a single emulated System.

In FIG. 3B, the Intra-Portal Links and IPL Ports are not visible, andthe Distributed Relay of the emulated Aggregation System C has oneGateway to each of the Systems in its Portal.

The purpose of the emulated Distributed Relay is to pass every framereceived from an Aggregation Port (“up frame”) to a Gateway, or todiscard it, and every frame received from a Gateway (“down frame”) to anAggregator Port, or discard it. The DR Functions comprising theDistributed Relay sometimes must send a frame across one or twoIntra-Portal Links in order to get it to the correct Gateway orAggregator Port. A DR Function makes the choice of whether to discard orpass a frame to its Gateway, Aggregator Port, or one of its IPLs byassigning every frame to two Conversation IDs, a Gateway Conversation IDand a Port Conversation ID, and configuring the Gateways, AggregationPorts, and IPLs in terms of these Conversation IDs.

The “Gateway algorithm” mentioned consists of two parts, an algorithmfor assigning any given frame to a Gateway Conversation ID, and anassignment of Gateway Conversation IDs to Gateways (e.g., usingDrni_Gateway_Conversation).

If the Portal System is a VLAN Bridge performing learning, the mappingof a frame to a Getaway Conversation ID will be based on its VLAN ID,otherwise the learning process breaks throughout the network. Forimplementations of DRNI in these cases there can be a one-to-one map ofVLAN ID to Conversation ID.

Similarly, the “Port algorithm” of item j in “Distributed Relays”section above consists of an algorithm for assigning any given frame toa Port Conversation ID, and an assignment of Port Conversation IDs toAggregation Ports (using aAggConversationAdminPort[ ] for example).

Means are specified herein below to ensure that all of the DR Functionson a given Portal use the same Gateway algorithm and the same Portalgorithm for assigning frames to their respective Conversation IDs, andto guarantee that any given Gateway Conversation ID is assigned to atmost one of the Gateways, and any given Port Conversation ID to at mostone of the Aggregation Ports of a Portal, at any given moment.

It is allowed, but not required, that the Gateway algorithm and the Portalgorithm use the same means for assigning a frame to a Conversation ID,so that the Gateway Conversation ID equals the Port Conversation ID.

The Port algorithm is always applied to a frame as it enters the DRFunction from the Gateway to determine whether to send it to theAggregator Port or to a particular IPP. The Gateway algorithm is alwaysapplied to a frame as it enters from the Aggregator Port to determinewhether to send it to the Gateway or to a particular IPP. Bothalgorithms have to be applied, and their results compared, in order toforward a frame entering a DR Function from an IPL, as shown in Table 1.

TABLE 1 DR Function: forwarding frame received from Intra-Portal Link nGateway algorithm Port algorithm says, DR Function says, “Gateway is . .. ” “Aggregation Port is . . . ” emits frame to: my Gateway Any* myGateway behind IPL n one of my my Aggregator Port Aggregation Portsbehind IPL n discard behind IPL m (≠n) IPL m (≠n) behind IPL m (≠n)any<Superscript>1 IPL m (≠n)

A) [1] “Any” means that the output from the Port algorithm is not used;the Gateway algorithm determines to which port the frame is sent.

B) [2] DR Functions in different Portal Systems have incompatibleconfigurations, or there is a malfunction. Discard frame to preventlooping.

C) Table 1 assumes one of three configurations:

-   Two Portal Systems connected by a single IPL;-   Three Portal Systems connected linearly by two IPLs; or-   Three Portal Systems connected circularly by three IPLs.

D) The Gateway algorithm is enforced in both directions through theGateway; that is, a frame entering the DR Function from a Gateway isdiscarded if the Gateway algorithm, applied to that frame, would notsend it back up the Gateway. This is necessary to prevent framesreceived from a Gateway being forwarded across an IPL and passed backinto the network through another Gateway.

E) If the Gateway algorithm indicates that the frame should pass throughthe Gateway, it must be an up frame, because a down frame could notenter the Portal from any other DR Function, by item D) above.

F) Otherwise, if the Gateway algorithm indicates that the frame camefrom the IPL to which it would be forwarded, then it is a down frame,and so is forwarded using the Port algorithm. (If the Port algorithmwould send it back on the port on which it arrived, there is some sortof malfunction or misconfiguration, and the frame is discarded.)

G) Otherwise, the Gateway algorithm indicates that the frame did notcome from the IPL to which it would be forwarded, so it must be an upframe, and the frame is directed according to the Gateway algorithm.

NOTE—The Port algorithm and Distributed Relay Control Protocol of theDistributed Relay together determine the mapping of Port ConversationIDs to individual Aggregation Ports, and the variables in their controldetermine the operation of the Frame Distributor and Frame Collector.However, this does not alter the path of data and control as described,since the Distributed Relay passes all data to or from the AggregationPorts through the Aggregator.

The application of the Gateway and Port algorithms on frames entering aDR Function from a Gateway and an Aggregator Port, as shown in Table 2and Table 3 respectively.

TABLE 2 DR Function: forwarding frame received from my Gateway Gatewayalgorithm Port algorithm says, DR Function says, “Gateway is . . . ”“Aggregation Port is . . . ” emits frame to: my Gateway one of my myAggregator Aggregation Ports Port behind IPL n IPL n behind IPL n anydiscard

TABLE 3 DR Function: forwarding frame received from one of myAggregation Ports Gateway algorithm Port algorithm says, DR Functionsays, “Gateway is . . . ” “Aggregation Port is . . . ” emits frame to:my Gateway any my Gateway behind IPL n any IPL n

Portal Topology

The most general topology of Portal is three Portal Systems connected ina ring by three Intra-Portal Links as illustrated in FIG. 21. Othersupported topologies according to other embodiments of the invention aresubsets of this, including:

-   -   Three Portal Systems connected in a chain by two IPLs,    -   Two Portal Systems connected by a single IPL,    -   A Portal System with no active IPLs.

The terms Home, Neighbor, and Other neighbor are used to identify thePortal Systems from the point of view of a given Intra-Portal Port. TheHome is the system containing the IPP. The Neighbor is the systemconnected to the IPP. The Other neighbor is the system connected to theother IPP (if present) in the Home system. Referring to FIG. 21, usingIPP B1 for an example, its home system is B, its immediate neighbor is A(because it is connected to IPP B1 via IPL AB), and its other neighboris C (because it is connected to IPP B2 via IPL BC). Note that the Otherneighbor of IPP A2 is also C (because it is connected to IPP A1 via IPLAC), so comparing the IDs of the Other neighbors of IPPs B1 and A2verifies that there are no more than three systems in a ring or chain.

Intra-Portal Link

An Intra-Portal Link (IPL) is a single logical point-to-point linkbetween DR Functions in two different Systems. A DR Function has at mostone IPL for each of the other Systems comprising one end of a DRNI LinkAggregation Group. IPLs and network links can share a physical link orlink aggregation (link aggregation being an aggregate of a set oflinks).

An IPL can be physical (e.g., an 802.3 Ethernet LAN) or logical (e.g., a802.1Q Backbone Service Instance or an IETF pseudowire). An Intra-PortalLink can share a physical link with other Intra-Portal Links or networklinks. An Intra-Portal Link can be a Link Aggregation Group, and thusconsist of a number of physical links.

It will often be the case in deployed networks that two Systems will beconfigured with both a normal network link connecting them, and an IPL,as illustrated in FIG. 4. It would reduce the utility of DRNI if everyPortal required its own separate physical IPL, especially if a pair ofSystems is configured to support multiple Portals. DRNI supports anumber of methods by which the Systems can distinguish frames on anetwork link from frames on a particular IPL:

-   Physical. A separate physical link can be used to support any    particular network link or IPL.-   Aggregated. A separate Aggregator Port can be used for supporting an    IPL.-   Time-shared. A network link and one or more IPLs can use the same    physical link (or Aggregator Port), but at different times. This    requires that the Systems disable the use of the network link when    the IPL is required for connectivity, or else that the use of the    Aggregation Links and the selection of Gateways be adjusted to    eliminate the need for using the IPL when the network link is    required. This technique is described herein.-   Tag-shared. A network link and one or more IPLs can use the same    physical link (or Aggregator Port), using different Service IDs. Tag    sharing is described herein.-   Logical. The frames on the network link and the IPL(s) can be    encapsulated, as described herein.

A System implementing the DRNI may support using separate physical linksfor IPLs and network links, and may support any of the other methods.

At each end of the shared physical link or Aggregator Port, there is onevirtual port for each function (network link or a particular IPL) thatthe link or Aggregator Port is used for. Any of the above methods can beused simultaneously between two Systems, by administrative choice, aslong as both ends of any given physical link or Aggregator Port use thesame method.

Network/IPL Sharing by Time

The goal of Network/IPL sharing by time is to support DRNI withoutrequiring separate physical links for a network connection and the IPL,and without requiring any frame modification. When sharing a link, it isnecessary to be able to determine for each frame whether that frame isintended to be traversing the network connection or the IPL. Thisdetermination can be made without modifying the frame (e.g. withouttranslating the VLAN ID or adding a tag or encapsulation) if at anygiven time the physical link is known to be only used as a network linkor only used as an IPL. Whether the link is used as a network link or anIPL at any given time is established by the control protocol used toestablish a fully-connected, loop-free active topology for each VLAN inthe network.

If the link is not included in the active topology of a VLAN (e.g. ithas been blocked by the operation of the network control protocol), itis available to be used as the IPL. In this case the link is used byDRNI just as if it were a dedicated (unshared) IPL.

If the link is included in the active topology of a VLAN, then there isno IPL available for that VLAN. In this case the DRNI is unable to passa frame between an Aggregation Port in one Portal System and a Gatewayin another Portal System. Therefore for any given frame, DRNI isrestricted to have the Gateway and the Aggregation Port in the samePortal System.

NOTE 1—The fact that the shared link can be unavailable for the transferof frames between a Gateway and a specific Aggregation Port does notrestrict the ability to exchange DRCPDUs on the shared link.

There are two cases to consider in meeting the restriction that for anygiven frame the Gateway and the Aggregation Port are in the same PortalSystem. The straightforward case is when the Port Conversation IDs areagreed and symmetric across the DRNI, and all frames with a given VLANID map to the Port Conversation IDs that select Aggregation Ports in thesame Portal System. Then that Portal System is selected as the Gatewayfor that VLAN ID, and there is no need for any data frames to traversethe IPL. In any other circumstance the only way to assure that theGateway and a specific Aggregation Port are in the same Portal System isthat when a frame is received on any port other than the sharednetwork/IPL port, that Portal System is considered the Gateway for thatframe and in each Portal System all Port Conversation IDs map to anAggregation Port attached to that System. In this mode, a Portal Systemwhich receives any frame on a network port (not being the IPP or theAggregation Port) is responsible for forwarding that frame to theAggregation Port if required. A Portal System which receives a frame onthe IPP never forwards that frame to the Aggregation Port. In this casethe gateway selection cannot necessarily be based on VID, so when thePortal Systems are 802.1Q Bridges the learning process on the sharednetwork/IPL link is compromised. Because the learning issues are limitedto this port, it can be remedied by synchronizing the addresses learnedon the DRNI with the other Portal System.

Network/IPL Sharing by Tag

If per-service frame distribution is employed, and if the number ofservices required to support the network link, plus the number ofservices required to support one or more IPLs, is less than the numberof services supplied by the frame format used (e.g., 4094 S-VLAN IDs),then VID translation can be used to separate the frames on the differentlogical links.

The method is selected by configuring the aDrniEncapsulationMethod withthe value 2. If enabled, as indicated by the variableEnabled_EncTag_Shared which is controlled by the Network/IPL sharingmachine, every frame which is to be transported by the IPL to theNeighbor Portal System and is associated with a Gateway Conversation ID,is translated to use a value configured in aDrniIPLEncapMap and everyframe, that is to be transported by network link, shared with the IPL,and is associated with a Gateway Conversation ID, is translated to use avalue configured in aDrniNetEncapMap.

Network/IPL Sharing by Encapsulation

This method enables sharing an IPL with a network link by usingencapsulation techniques (e.g., an 802.1Q Backbone Service Instance, aB-VLAN, an IETF pseudowire, etc.)

The method is selected by configuring the aDrniEncapsulationMethod witha value representing the encapsulation method that is used to transportIPL frames (date frames passing through an IPL, i.e., non DRCPDUcarrying frames) to the Neighbor Portal System when the IPL and networklink are sharing the same physical link. This value consists of thethree-octet Organization Unique Identifier (OUI) identifying theorganization which is responsible for this encapsulation and onefollowing octet used to identify the encapsulation method defined bythat organization. If enabled, as indicated by the variableEnabled_EncTag_Shared which is controlled by the Network/IPL sharingmachine, every frame, that is to be transmitted on the IPL to theNeighbor Portal System and is associated with a Gateway Conversation ID,is encapsulated with a method specified by aDrniEncapsulationMethod touse a value configured in aDrniIPLEncapMap and every frame, that isreceived by the IPL is de-encapsulated and mapped to a GatewayConversation ID using the same table.

DR Function State Machine

The DR Function state machines shall implement the forwarding rulesspecified in Tables 1-3.These forwarding rules can be summarized asfollows:

-   a) For frames entering through an Aggregation Port, Up frames, the    Gateway algorithm decides whether to transmit it to the Gateway link    or to the IPP according to its Gateway Conversation ID. If the    frame's Gateway Conversation ID matches the Portal System's    operational Gateway Conversation ID, the frame will be forwarded to    the Gateway, otherwise it will be forwarded to the IPP.-   b) For frames entering through a Gateway, Down frames, the Port    algorithm decides whether to transmit it to the Aggregation Port or    to the IPP according to its Port Conversation ID. If the frame's    Port Conversation ID matches the Portal System's operational Port    Conversation ID, the frame will be forwarded to the Aggregation    Port, otherwise it will be forwarded to the IPP.-   c) An Up frame offered to an IPP is only transmitted if the Portal    System for this Gateway Conversation ID lies behind that IPP,    otherwise it is discarded.-   d) A Down frame offered to an IPP is only transmitted if the target    Portal System for this Port Conversation ID lies behind that IPP,    otherwise it is discarded.

Some of the Link Aggregation variables used by a Distributed Relay haveto be formed in a particular manner, so that multiple Portal Systems cancooperate to create a single emulated System:

-   e) The two least significant bits of the Port Priority in the Port    ID for each Aggregation Port in a Distributed Relay's Aggregator    Port are set to the value of DRF_Portal_System_Number. The remainder    of the bits is assigned a value unique within the DR Function.-   f) The most significant two bits of the Administrative Key for each    Aggregation Port and associated Aggregator in a Distributed Relay's    Aggregator Port is set to the value of DRF_Portal_System_Number. The    remainder of the bits can be used as described to reflect the    physical characteristics of the Aggregation Ports.

Service Interfaces

Since a DR Function uses various instances of the ISS, it is necessaryto introduce a notation convention so that the reader can be clear as towhich interface is being referred to at any given time. A prefix istherefore assigned to each service primitive, indicating which of theinterfaces is being invoked. The prefixes are as follows:

-   a) Agg:, for primitives issued on the interface between the DR    Function and the Link Aggregation sublayer.-   b) Gate:, for primitives issued on the Gateway.-   c) MacIppN:, for primitives issued on the interface between the MAC    entities supporting the IPL n and the DRCP Control    Parser/Multiplexer.-   d) DRCPCtrlMuxN:, for primitives issued on the interface between    DRCP Control Parser/Multiplexer N and the DRCP control entity (where    N is identifying the IPP associated with the DRCP Control    Parser/Multiplexer).-   e) IppN:, for primitives issued on the interface of the DR Function    supported by the DRCP Control Parser/Multiplexer N (where N is    identifying the IPP associated with the DRCP Control    Parser/Multiplexer).

Per-DR Function Variables

The following discussion focuses on a variety of pre-DR functionvariables according to one embodiment of the invention.

DA: Destination Address

SA: Source Address

mac_service_data_unit

Priority: The parameters of the M_UNITDATA.indication primitive.

BEGIN: A Boolean variable that is set to TRUE when the System isinitialized or reinitialized, and is set to FALSE when(re-)initialization has completed.

Value: Boolean

Drni_Portal_System_Gateway_Conversation: Operational Boolean vector,indexed by Gateway Conversation ID, indicating whether the indexedGateway Conversation ID is allowed to pass through this DR function'sGateway (TRUE=passes). Its values are computed by theupdatePortalSystemGatewayConversation function in one embodiment Inanother embodiment, this variable is constructed from theDrni_Gateway_Conversation, by setting to FALSE, all the indexed GatewayConversation ID entries that are associated with other Portal Systems inthe Portal and, of the remaining indexed Gateway Conversation IDentries, all that are not in agreement with other Portal Systems.

Value: sequence of Boolean values, indexed by Gateway Conversation ID.

Drni_Portal_System_Port_Conversation: Operational Boolean vector,indexed by Port Conversation ID, indicating whether the indexed PortConversation ID is allowed to be distributed through this DR function'sAggregator (TRUE=passes). Its values are computed by theupdatePortalSystemPortConversation in one embodiment. In anotherembodiment, this variable is constructed from theDrni_Port_Conversation, by setting to FALSE all the indexed PortConversation ID entries that are associated with other Portal Systems inthe Portal and, of the remaining indexed Gateway Conversation IDentries, all that are not in agreement with other Portal Systems.

Value: sequence of Boolean values, indexed by Port Conversation ID.

Messages

Agg:M_UNITDATA.indication

Gate:M_UNITDATA.indication

IppN:M_UNITDATA.indication

Agg:M_UNITDATA.request

Gate:M_UNITDATA.request

IppN:M_UNITDATA.request

The service primitives used to pass a received frame to a client withthe specified parameters.

If Network/IPL sharing by tag, or Network/IPL sharing by encapsulationmethods are used, the service primitives IppN:M_UNITDATA.indication andIppN:M_UNITDATA.request need to be manipulated through the operation offunctions which are controlled by the Network/IPL sharing machine

DR Function: Aggregator Port Reception State Machine

The DR Function: Aggregator Port reception state machine may implementthe function specified in FIG. 22 with its associated parametersaccording to one embodiment of the invention. There is one DR Function:Aggregator Port reception state machine per Portal System and there areas many PASS_TO_IPP_N states as IPPs in a Portal System, each identifiedby the index n, the prefix “n.” in the diagram is used to identify thespecific IPP n that the associated variable is related to.

DR Function: Gateway Distribution State Machine

The DR Function: Gateway distribution state machine may implement thefunction specified in FIG. 23 with its associated parameters accordingto one embodiment of the invention. There is one DR Function: Gatewaydistribution state machine per Portal System and there are as manyPASS_TO_IPP_N states as IPPs in a Portal System, each identified by theindex n. The prefix “n.” in the diagram is used to identify the specificIPP n that the associated variable is related to.

DR Function: IPP N Reception State Machine

The DR Function: IPP N reception state machine may implement thefunction specified in FIG. 24 with its associated parameters accordingto one embodiment of the invention. There is one DR Function: IPP Nreception state machine per IPP per Portal System and there are as manyPASS_TO_IPP_M states as IPPs in a Portal System, each identified by theindex m. The prefix “n.” or “m.” in the diagram is used to identify thespecific IPP n or IPP m that the associated variable is related to.

Distributed Relay Control Protocol

The purpose of the Distributed Relay Control Protocol (DRCP) is to:

A) Establish communication between Portal Systems across an Intra-PortalLink;

B) Verify the consistent configuration of Portal Systems;

C) Determine the identity to be used for the emulated system;

D) Distribute the current states of the Portal Systems and theirAggregation Ports among each other;

E) Compute the resultant path of any frame required to pass through eachIPL, and exchange the information with adjacent Portal Systems asrequired to ensure against forwarding loops and duplicate framedelivery.

F) Exchange information among Portal Systems in order to supportdistributed functions not specified in this specification;

The result of the operation of DRCP is to maintain the variables thatcontrol the forwarding of frames by the Distributed Relay.

DRCP exchanges information to ensure that the Portal Systems can worktogether. The first class of such information includes the managedobjects and variables that must be compatible in order to pass any dataat all (item A above). In one embodiment, these include:

G) aAggPortAlgorithm: All Portal Systems must use the same Portalgorithm.

H) aDrniGatewayAlgorithm: All Portal Systems must use the same Gatewayalgorithm.

I) aDrniPortalId: All Portal Systems must have the same value foraDrniPortalId, to ensure that they are all supposed to belong to thesame Portal.

J) for aDrniPortalTopology: All Portal Systems have to have the samevalue for aDrniPortalTopology and in the case of a Portal of threePortal Systems connected in a ring, the same “Loop Break Link”,aDrniLoopBreakLink needs to be configured consistently through thePortal

K) aDrniPortalSystemNumber: All Portal Systems must have differentaDrniPortalSystemNumber values, and all of these values must be in therange 1 . . . 3, to ensure that information can be labeled meaningfully.

L) aAggActorAdminKey: The most significant two bits of theAdministrative Key for each Aggregator in a Distributed Relay'sAggregator Port is set to the value of DRF_Portal_System_Number. Theremainder of the bits reflect the physical characteristics of theassociated Aggregation Ports and they have to be the same for all PortalSystems in the Portal.

The second class of managed objects (item B) control through whichGateway and which Aggregation Ports each Conversation ID passes. Forthese managed objects, if the information about one Conversation ID isconfigured differently in different Portal Systems, only thatConversation ID is affected. Therefore, the Portal can operate normally,and the mechanisms that ensure against duplicate delivery or forwardingloops will block the passage of any frames belonging to misconfiguredConversation IDs. In order to detect misconfiguration, so that theblocking is not permanent, the DR Functions can notify the networkadministrator if the configurations differ. Since these configurationsare quite large, a checksum of their contents is exchanged, rather thanthe configurations, themselves. This method detects differences to ahigh probability, but not a certainty. In one embodiment, these managedobjects include:

L) aDrniConvAdminGateway[ ]: The list that is used to dynamicallydetermine which Conversation ID flows through which Gateway.

M) aAggConversationAdminPort[ ]: The list that is used to dynamicallydetermine which Conversation ID flows through which Aggregation Port.

DRCP uses its information on which of the expected Portal Systems are orare not connected via IPLs to determine the identity of the emulatedDistributed Relay (item C above in this section).

The current operational states of all of the Portal Systems and theirAggregation Ports is exchanged so that each of the DR Functions candetermine to which Portal System's Gateway or Aggregator Port each frameis to be delivered (item D above in this section). Each DR Functioncomputes a vector specifying exactly which Port Conversation IDs andwhich Gateway Conversation IDs can pass through each Gateway,Aggregation Port, or IPP. On each IPP, this information is exchanged(item E above in this section). If there is a difference between two DRFunctions' vectors for any given Conversation ID, the output variablesare set so that the DR Function will block frames with that ConversationID. This prevents looping or duplicate delivery of any frame.

Establishing the Portal and Distributed Relay

The creation of Portals automatically is not specified direction.Instead, DRCP compares the network administrator's intentions, asdefined by managed objects, to the physical topology of the configuredSystems, and if the connected Systems' configurations are compatible,DRCP establishes and enables the operation of the Portal. In order toestablish a Distributed Relay across a Portal, a network administratorconfigures the following managed objects

A) There may be many Systems in a network, and some or all of theselected Portal Systems may participate in other Portals. Determiningwhich other Portal Systems belong to this Portal System's Portal isaccomplished by configuring variables such as aDmiPortalId andaDrniPortalSystemNumber.

B) As described herein above, any point-to-point instance of the MACService can be assigned to be an Intra-Portal Link. The particularinstances assigned to the use of a DR Function are configured inaDrniIntraPortalLinkList for example.

C) Which Aggregator in each Portal System is to be assigned to this DRFunction is configured in aDrniAggregator in one embodiment.

D) The methods to be used by the DR Functions to assign frames toGateway Conversation IDs and Port Conversation IDs are configured in twomanaged objects, aDrniGatewayAlgorithm and aAggPortAlgorithm in oneembodiment.

E) The initial and backup assignments of Conversation IDs to Gatewaysand Aggregation Ports to cover failure modes are configured in severalmanaged objects: aDrniConvAdminGateway[ ], andaAggConversationAdminPort[ ] in one embodiment.

DRCPDU Transmission, Addressing, and Protocol Identification

Distributed Relay Control Protocol Data Units (DRCPDUs) are transmittedand received using the service provided by an LLC entity that uses, inturn, a single instance of the MAC Service provided at an MSAPassociated with an IPP. Each DRCPDU is transmitted as a single MACservice request, and received as a single MAC service indication, withthe following parameters:

-   destination address-   source address-   MSDU (MAC Service Data Unit)-   priority

The MSDU of each request and indication comprises a number of octetsthat provide EtherType protocol identification followed by the DRCPDUproper.

NOTE 1—For the purposes of this standard, the term “LLC entity” includesentities that support protocol discrimination using the EtherType fieldas specified in IEEE Std 802.

NOTE 2—The complete format of an DRCP frame depends not only on theDRCPDU format, as specified here, but also on the media access methoddependent procedures used to support the MAC Service.

Destination MAC address

The destination address for each MAC service request used to transmit aDRCPDU may be a group address selected by IPP Managed Objects. Itsdefault values may be the nearest non-TPMR (Two-Port Media AccessControl (MAC) Relay) Bridge group address.

Source MAC address: The source address for each MAC service request usedto transmit a DRCPDU may be an individual address associated with theIPP MSAP (MAC Service Access Point) at which the request is made.

Priority: The priority associated with each MAC service request shouldbe the default associated with the IPP MSAP.

Encapsulation of DRCPDUs in Frames

A DRCPDU is encoded in the mac_service_data_unit parameter of anM_UNITDATA.request or M_UNITDATA.indication. The first octets of themac_service_data_unit are a protocol identifier, followed by the DRCPDU,followed by padding octets, if any, as required by the underlying MACservice.

Where the ISS instance used to transmit and receive frames is providedby a media access control method that can support EtherType encodingdirectly (e.g., is an IEEE 802.3 MAC), the protocol identifier is twooctets in length. All DRCPDUs are identified by the EtherType specified.Where the ISS instance is provided by a media access method that cannotdirectly support EtherType encoding (e.g., is an IEEE 802.11 MAC), theTPID is encoded according to the rule for a Subnetwork Access Protocol(Clause 10 of IEEE Std 802) that encapsulates Ethernet frames over LLC,and comprises the SNAP header (hexadecimal AA-AA-03) followed by theSNAP PID (hexadecimal 00-00-00) followed by the Protocol's EtherType(hexadecimal xx-xx).

DRCPDU Structure and Encoding

Transmission and Representation of Octets

All DRCPDUs comprise an integral number of octets. The bits in eachoctet are numbered from 0 to 7, where 0 is the low-order bit. Whenconsecutive octets are used to represent a numerical value, the mostsignificant octet is transmitted first, followed by successively lesssignificant octets.

When the encoding of (an element of) a DRCPDU is depicted in a diagram:

A) Octets are transmitted from top to bottom.

B) Within an octet, bits are shown with bit 0 to the left and bit 7 tothe right, and are transmitted from left to right.

C) When consecutive octets are used to represent a binary number, theoctet transmitted first has the more significant value.

D) When consecutive octets are used to represent a MAC address, theleast significant bit of the first octet is assigned the value of thefirst bit of the MAC address, the next most significant bit the value ofthe second bit of the MAC address, and so on through the eighth bit.Similarly, the least significant through most significant bits of thesecond octet are assigned the value of the ninth through seventeenthbits of the MAC address, and so on for all the octets of the MACaddress.

Encapsulation of DRCPDUs in Frames

A DRCPDU is encoded in the mac_service_data_unit parameter of anM_UNITDATA.request or M_UNITDATA.indication in one embodiment. The firstoctets of the mac_service_data_unit are a protocol identifier, followedby the DRCPDU, followed by padding octets, if any, as required by theunderlying MAC service.

Where the ISS instance used to transmit and receive frames is providedby a media access control method that can support EtherType encodingdirectly (e.g., is an IEEE 802.3 MAC), the protocol identifier is twooctets in length, and the value is the Protocol's EtherType (hexadecimalxx-xx).

Where the ISS instance is provided by a media access method that cannotdirectly support EtherType encoding (e.g., is an IEEE 802.11 MAC), theTPID is encoded according to the rule for a Subnetwork Access Protocol(Clause 10 of IEEE Std 802) that encapsulates Ethernet frames over LLC,and comprises the SNAP header (hexadecimal AA-AA-03) followed by theSNAP PID (hexadecimal 00-00-00) and EtherType (hexadecimal xx-xx).

DRCPDU Structure

FIG. 5 illustrates one embodiment of the DRCPDU structure according tothe invention. The fields are defined as the following:

A) Subtype. The Subtype field identifies the specific Slow Protocolbeing encapsulated. DRCPDUs carry the Subtype value 0x0X. Note A) not bepresent if the choice is not the use the Slow Protocol EtherType toidentify DCRP operation.

B) Version Number. This identifies the DRCP version; implementationsconformant to one embodiment carries the value 0x01.

C) TLV_type=Portal Information. This field indicates the nature of theinformation carried in this TLV-tuple. DRNI information is identified bythe value 0x01 in one embodiment.

D) Portal_Information_Length. This field indicates the length (inoctets) of this TLV-tuple, Actor information uses a length value of 18(0x12) in one embodiment.

E) Aggregator_Priority. The priority assigned to the Actor System ID (bymanagement or administration policy) of the Aggregator attached to theDR Function, encoded as an unsigned integer from aAggActorSystemPriorityin one embodiment.

F) Aggregator_ID. The MAC address component of Actor System ID of theAggregator attached to the DR Function from a in one embodiment.

G) Portal_Priority. The priority assigned to Portal ID (by management oradministration policy), encoded as an unsigned integer fromaDrniPortalPriority in one embodiment.

H) Portal_ID. The MAC address component of Portal IDs from aDrniPortalIdin one embodiment.

I) TLV_type=Portal Configuration Information. This field indicates thenature of the information carried in this TLV-tuple. PortalConfiguration Information is identified by the value 0x02 in oneembodiment.

J) Portal_Configuration_Information_Length. This field indicates thelength (in octets) of this TLV-tuple, Portal Configuration Informationuses a length value of 46 (0x2E) in one embodiment.

K) Topology_State. This DR Function's topology related variables for theIPP, encoded as individual bits within a single octet, as follows and asillustrated in FIG. 6C:

1) Portal_System_Number is encoded in bits 0 and 1. It is the PortalSystem Number of this DR Function from aDrniPortalSystemNumber.

2) Portal_Topology is encoded in bits 2 and 3. It is the Portal Topologyof this DR Function as configured in aDrniPortalTopology.

3) Neighbor_Conf_Portal_System_Number is encoded in bits 4 and 5. It isthe configured Portal System Number of the Portal System that isattached to this IPP.

4) Loop_Break_Link is encoded in bit 6. This flag indicates that the IPLattached to this IPP is configured as a Loop Break Link. TRUE indicatesthat the IPL is configured in aDrniLoopBreakLink and is encoded as a 1;otherwise, the flag is encoded as a 0.

5) Bit 7 is reserved for future use. It set to 0 on transmit and it isignored on receipt.

K2) Topology_State. In an alternate embodiment, topology state may beencoded in a different octet, as follows and as illustrated in FIG. 29.

1) Portal_System_Number is encoded in bits 0 and 1. The Portal SystemNumber of this DR Function from aDrniPortalSystemNumber in oneembodiment.

2) Neighbor_Conf_Portal_System_Number is encoded in bits 2 and 3. Theconfigured Portal System Number of the Portal System that is attached tothis IPP in one embodiment.

3) Bits 4 to 6 are reserved for future use. They are set to 0 ontransmit and they are ignored on receipt in one embodiment.

4) Other_Non_Neighbor in encoded in bit 7. TRUE (encoded as 1) indicatesthat the Other Ports Information TLV is not associated with an immediateNeighbor of this Portal System. FALSE (encoded as 0) indicates that theOther Ports Information TLV is an immediate Neighbor on the other IPP onthis Portal System in one embodiment.

L) Oper_Aggregator_Key. The current operational Aggregator Key value ofthe Aggregator attached to the DR Function.

M) Port_Algorithm. The Port algorithm used by this DR Function andAggregator from aAggPortAlgorithm in one embodiment.

N) Gateway_Algorthm. The Gateway algorithm used by this DR Function fromaDrniGatewayAlgorithm in one embodiment.

O) Port_Digest. A digest of this DR Function's prioritized PortConversation ID-to-Aggregation Port assignments fromaAggConversationAdminPort[ ] in one embodiment.

P) Gateway_Digest. A digest of this DR Function's prioritized GatewayConversation ID-to-Gateway assignments from aDrniConvAdminGateway[ ] inone embodiment.

Q) TLV_type=DRCP State. This field indicates the nature of theinformation carried in this TLV-tuple. DRCP State is identified by thevalue 0x03 in one embodiment.

R) DRCP_State_Length. This field indicates the length (in octets) ofthis TLV-tuple, DRCP State uses a length value of 3 (0x03) in oneembodiment.

S) DRCP_State. This DR Function's DRCP variables for the IPP, encoded asindividual bits within a single octet, as follows and as illustrated inFIG. 6B:

1) Home_Gateway. In one embodiment, it is encoded in bit 0. This flagindicates the operation state of this DR Functions' Gateway. TRUEindicates operational and is encoded as a 1 and non-operational isencoded as a 0.

2) Neighbor_Gateway is encoded in bit 1 in one embodiment. This flagindicates the operation state of the Neighbor's DR Functions' Gateway.TRUE indicates operational and is encoded as a 1 and non-operational isencoded as a 0.

3) Other_Gateway is encoded in bit 2 in one embodiment. This flagindicates the operation state of a potential other DR Functions'Gateway. TRUE indicates operational and is encoded as a 1 andnon-operational is encoded as a 0.

4) IPP_Activity is encoded in bit 3 in one embodiment. This flagindicates the Neighbor's DRCP Activity on this IPP. Active DRCP Neighboris encoded as a 1 and no DRCP activity is encoded as 0.

5) DRCP_Timeout is encoded in bit 4 in one embodiment. This flagindicates the Timeout control value with regard to this link. ShortTimeout is encoded as a 1 and Long Timeout is encoded as a 0.

6) Gateway Sync is encoded in bit 5 in one embodiment. If TRUE (encodedas a 1), this DR Function considers this IPP's Neighbor Partner Systemsto have their Gateways IN_SYNC; i.e., this Portal System's operationalvector listing which Portal System's Gateway (if any) is passing eachGateway Conversation ID is in agreement with this IPP's Neighbors'operational vector. If FALSE (encoded as a 0), then this IPP iscurrently OUT_OF_SYNC; i.e., this IPP' s Neighbors' operational vectorlisting which Portal System's Gateway (if any) is passing each GatewayConversation ID is in disagreement.

7) Port Sync is encoded in bit 6. If TRUE (encoded as a 1), this DRFunction considers this IPP's Neighbor Partner Systems to have theirAggregator Ports IN_SYNC; i.e., this Portal System's operational vectorlisting which Portal System's Aggregation Port (if any) is passing eachPort Conversation ID is in agreement with this IPP's Neighbors'operational vector. If FALSE (encoded as a 0), then this IPP iscurrently OUT_OF_SYNC; i.e., this IPP's Neighbors' operational vectorlisting which Portal System's Aggregation Port (if any) is passing eachPort Conversation ID is in disagreement.

8) Expired is encoded in bit 7. If TRUE (encoded as a 1), this flagindicates that the DR Function's Receive machine is in the EXPIRED orDEFAULTED state; if FALSE (encoded as a 0), this flag indicates that theDR Function's Receive machine is not in the EXPIRED nor DEFAULTED state.

The received values of Expired state are not used by DRCP; however,knowing their values can be useful when diagnosing protocol problems.Also note that the order of the fields and the length of the fields maybe different in a different embodiment but still complies with thespirit of this invention.

T) TLV_type=Home Ports Information. This field indicates the nature ofthe information carried in this TLV-tuple. Home Ports information isidentified by the integer value 0x04 in one embodiment.

U) Home_Ports_Information_Length. This field indicates the length (inoctets) of this TLV-tuple, Home Ports information uses a length value of4 times the number of this Portal System's Aggregation Ports that areincluded.

V) Home_Admin_Aggregator_Key. The administrative Aggregator Key value ofthe Aggregator attached to this DR Function from aAggActorAdminKey.

W) Home_Oper_Partner_Aggregator_Key. The operational Partner AggregatorKey associated with this Portal System's Aggregator LAG ID.

X) Active Home Ports. The list of active Aggregation Ports in increasingPort Number order. The list is controlled by the operation of LACP(listing all the Ports on this Portal System for which LACP is declaringActor_Oper_Port_State.Distributing=TRUE).

Y) TLV_type=Neighbor Ports Information. This field indicates the natureof the information carried in this TLV-tuple. Neighbor Ports informationis identified by the integer value 0x05.

Z) Neighbor_Ports_Information_Length. This field indicates the length(in octets) of this TLV-tuple, Neighbor Ports information uses a lengthvalue of 4 times the number of the Neighbor Aggregation Ports that areincluded.

Aa) Neighbor_Admin_Aggregator_Key. The administrative Aggregator Keyvalue of the Aggregator attached to the Neighbor Portal System.

Ab) Neighbor_Oper_Partner_Aggregator_Key. The operational PartnerAggregator Key associated with the Neighbor Portal System's AggregatorLAG ID.

Ac) Active Neighbor Ports. The list of active Aggregation Ports inincreasing Port Number order. The list is controlled by the operation ofLACP (listing all the Ports on the immediate Neighbor Portal System forwhich LACP is declaring Actor_Oper_Port_State.Distributing=TRUE).

Ad) TLV_type=Other Ports Information. This field indicates the nature ofthe information carried in this TLV-tuple. The Other Ports informationis identified by the integer value 0x06. This TLV is only used if thePortal Topology contains three Portal Systems.

Ae) Other_Ports_Information_Length. This field indicates the length (inoctets) of this TLV-tuple, Other Ports information uses a length valueof 4 times the number of the Other Portal System's Aggregation Portsthat are included.

At) Other_Admin_Aggregator_Key. The administrative Aggregator Key valueof the Aggregator attached to the other neighbor Portal System.

Ag) Other_Oper_Partner_Aggregator_Key. The operational PartnerAggregator Key associated with the other neighbor Portal System'sAggregator LAG ID.

Ah) Active Other Ports. The list of active Aggregation Ports inincreasing Port Number order. The list is controlled by the operation ofLACP (listing all the Ports on an optional other Portal System for whichLACP is declaring Actor_Oper_Port_State.Distributing=TRUE).

Ai) TLV_type=Other Information. This field indicates the nature of theinformation carried in this TLV-tuple. Other information is identifiedby the integer value 0x0x in one embodiment.

Aj) TLV_type=Terminator. This field indicates the nature of theinformation carried in this TLV-tuple. Terminator (end of message)information is identified by the integer value 0x00 in one embodiment.

Ak) Terminator_Length. This field indicates the length (in octets) ofthis TLV-tuple. Terminator information uses a length value of 0 (0x00)in one embodiment.

Note, the use of a Terminator_Length of 0 is intentional. In TLVencoding schemes it is common practice for the terminator encoding to be0 both for the type and the length.

Also note, the Version 1 implementation is guaranteed to be able toreceive version N PDUs successfully, although version N PDUs may containadditional information that cannot be interpreted (and will be ignored)by the Version 1. A crucial factor in ensuring backwards compatibilityis that any future version of the protocol is required not to redefinethe structure or semantics of information defined for the previousversion; it may only add new information elements to the previous set.Hence, in a version N PDU, a Version 1 implementation can expect to findthe Version 1 information in exactly the same places as in a Version 1PDU, and can expect to interpret that information as defined for Version1.

Note, that he DRCPDU grows in size with the number of Aggregation Ports.A maximum of (1500−88)/4=353 Aggregation Ports spread across a Portal'sPortal Systems are supported. The minimum number of Aggregation Portsthat need to be supported by a Portal is two.

The table below provides a list of the TLVs that are applicable forDRCP.

TABLE 4 Type field values of DRCP TLVs TLV Type Field Terminator TLV0x00 Portal Information TLV 0x01 Portal Configuration Information TLV0x02 DRCP State TLV 0x03 Home Ports Information TLV 0x04 Neighbor PortsInformation TLV 0x05 Other Ports TLV 0x06 Network/IPL Sharing Method TLV0x07 Network/IPL Sharing Encapsulation TLV 0x08 Reserved for IEEE 802.10x09-0x0E Organization Specific TLV 0x0F Reserved for IEEE 802.10x10-0xFF

Embodiments thus provide encapsulation of DRCPDUs into frames, whereineach DRCPDU comprises a field indicating DRCP state, such as DRCPvariables for an IPP. The field may be one octet. The field may furtherinclude, encoded in the different bits of the octet, information statingone or more of the following: Home_Gateway; Neighbor_Gateway;Other_Gateway; IPP_Activity; DRCP_Timeout; Gateway Sync; Port Sync;Expired.

FIG. 14 illustrates another embodiment of the DRCPDU structure accordingto the invention. While the DRCPDU structure in FIG. 14 is similar tothat of FIG. 5, several fields are different. For example, theHome_Ports_Information_Length is 2+4*PN in FIG. 14, not 2+2*PN as inFIG. 5. Similarly, several other fields of the DRCPDU structure in FIG.14 contain lengths different from those of the DRCPDU structure in FIG.5, and the two DRCPDU structures also contain fields not present in theother embodiment. In each example DRCPDU structure, the fields havedescriptive names for the content of the fields. Some of the differingfields contain similar information, but have been renamed orreorganized. One skilled in the art would understand that other similarDRCPDU structures are possible consistent with the principles andstructures described herein.

FIG. 25 illustrates another embodiment of the DRCPDU structure accordingto the invention. The DRCPDU structure in FIG. 25 is similar to that ofFIGS. 5 and 14 with several differences. For example, the Portinformation lengths (for home, neighbor, and other ports) aredifference. In addition, the DRCPDU structure in FIG. 25 includes atopology state, and several fields for aggregator keys such asOper_Aggregator_Key, Home_Admin_Aggregator_Key,Home_Oper_Partner_Aggregator_Key, Neighbor_Admin_Aggregator_Key,Other_Admin_Aggregator_Key, and Other_Oper_Partner_Aggregator_Keydiscussed herein above.

FIG. 32 illustrates a method of communicating through a frame includingDRCPDU structure according to one embodiment of the invention. Method3200 may be implemented on a DRCP node (e.g., a network device) of aDRCP portal (referred to as a local portal) as a part of a DRNI such asnodes K-O of FIG. 1B and network devices 132 and 134 of FIG. 1C.

At 3202, a DRCP node of a portal encapsulate a DRCPDU in a frame. TheDRCPDU includes a structure including (1) a type field (referred to assubtype) indicating the PDU is for DRCP, (2) a version field indicatingthe version number of the DRCPDU, and (3) a set of TLVs. The set of TLVsincludes a terminator TLV, a portal information TLV, a portalconfiguration TLV, a DRCP state TLV, a home ports information TLV, and aneighbor ports information TLV. When a portal includes more than twonodes, the PDU structure may include another ports TLV in oneembodiment.

In one embodiment, the set of TLVs further include at least one ofnetwork/IPL sharing method TLV, network/IPL sharing encapsulation TLV,one or more TLVs reserved for IEEE 802.1, and organization specificTLVs, each TLV being discussed herein.

Each of the set of TLVs include a TLV type field. In one embodiment, theTLV type field of each includes values specified in Table 4 illustratedabove. Each of the TLVs includes fields which may set to valuesdiscussed herein above. For example:

-   The terminator TLV indicates the end of the PDU structure. In one    embodiment, it includes a TLV type field and a terminator length    field, where the terminator length field indicate a length of zero    as discussed herein above.-   The portal information TLV indicates characteristics of the portal,    of which the DRCP node belongs to. In one embodiment, the    characteristics are indicated in (1) an aggregator priority field    indicating a priority assigned to the aggregator of the node, (2) an    aggregator identifier (ID) field indicating an ID of the    aggregator, (3) a portal priority field indicating a priority    assigned to the portal, and (4) a portal address field indicating an    MAC address component associated with the network device as    discussed herein above.-   The portal configuration information TLV indicates configuration    information of the portal, of which the DRCP node belongs to. In one    embodiment, the configuration information is indicated in (1) a    topology state field indicating a topology state of the portal such    as illustrated in FIGS. 6C and 29, (2) an operational aggregator key    field indicating an operational aggregator key of the node, (3) a    portal algorithm field indicating a portal algorithm used, (4) a    gateway algorithm field indicating a gateway algorithm used, (5) a    port digest field indicating a port digest used for port    conversation identifier (ID) to aggregation port assignment, and (6)    a gateway digest field indicating a gateway digest used for gateway    conversation ID to gateway assignment as discussed herein above.-   The DRCP state TLV indicates variables associated with the IPP. In    one embodiment, the DRCP state includes values encoded as    illustrated in FIG. 6B as discussed herein above.-   The home ports information TLV indicates current status of the node    in association with the DRCP node. In one embodiment, the current    status of the node is indicated in (1) an administrative aggregator    key field indicating an administrative aggregator key value of the    aggregator attached, (2) an operational partner aggregator key field    indicating an operational partner aggregator key associated with the    node's aggregator LAG ID, (3) an active aggregation port field    indicating a list of active aggregation ports in the node as    discussed herein above.-   The neighbor ports information TLV indicates current status of the    neighbor node in association with the DRNI. In one embodiment, the    current status of the neighbor node is indicated in (1) an    administrative aggregator key field indicating an administrative    aggregator key value of the aggregator attached to the neighbor    network device, (2) an operational partner aggregator key field    indicating an operational partner aggregator key associated with the    neighbor node's aggregator LAG ID, and (3) an active aggregation    port field indicating a list of active aggregation ports in an    immediate neighbor portal system associated with the IPP as    discussed herein above.-   The other ports information TLV indicates current status of the    other neighbor node associated with the DRNI when the local portal    includes more than two nodes. In one embodiment, the current status    of the other neighbor node is indicated in (1) an administrative    aggregator key field indicating an administrative aggregator key    value of the aggregator attached to the other node, (2) an    operational partner aggregator key field indicating an operational    partner aggregator key associated with the other neighbor node's    aggregator LAG ID, and (3) a list of active aggregation ports in the    other neighbor node on the IPP as discussed herein above.-   The network/IPL sharing method TLV indicates a network and IPL    sharing method associated with the node; and-   The network/IPL sharing encapsulation TLV indicates information    relating to encapsulation of the sharing method.

At 3206, the DRCP node sends the frame to its neighbor node of theportal via the IPP, wherein the neighbor node uses the encapsulatedinformation to control forwarding of frames.

As discussed herein above, through method 3200, the node exchangesinformation with its neighbor node and thus establishes and enables DRCPoperations of the portal. Method 3200 provides an efficient way for thenode to exchange information with its neighboring node.

Network/IPL Sharing TLV

These TLVs are only required when the Network/IPL sharing method used isone of Network/IPL sharing by tag, or Network/IPL sharing byencapsulation in order to ensure consistent configuration among thePortal Systems. The Network/IPL sharing by time method requires theexchange of the Network/IPL Sharing Method TLV but not the Network/IPLSharing Encapsulation TLV.

NOTE—No Network/IPL sharing TLVs are required when the Network/IPLsharing method used is the physical or aggregated method discussedherein.

The following table provides a list of the TLVs that are applicable forNetwork/IPL sharing methods.

TABLE 5 Type field values of Network/IPL sharing TLVs TLV Type FieldNetwork/IPL Sharing Method TLV 0x07 Network/IPL Sharing EncapsulationTLV 0x08

Network/IPL Sharing Method TLV

The network/IPL sharing method TLV structure may be shown as table belowand as further described in the following field definitions:

TABLE 6 Network/IPL Sharing Method TLV Length TLV (Octets) TLV_type =Network/IPL Sharing_Method 1 Network/IPL_Sharing_Method_Length = 6 1DRF_Home_Network/IPL_Sharing_Method 4

TLV_type=Network/IPL Sharing Method TLV. This field indicates the natureof the information carried in this TLV-tuple. The Network/IPL sharingTLVs is identified by the integer value 0x07.

Network/IPL_Sharing_Method_Length. This field indicates the length (inoctets) of this TLV-tuple. The Network/IPL sharing TLVs uses a lengthvalue of 6 (0x06). DRF_Home_Network/IPL_Sharing_Method. This fieldcontains the value representing the Network/IPL sharing method that isused to transport IPL frames to the Neighbor Portal System on this IPPwhen the IPL and network link are sharing the same physical link. Itconsists of the three-octet Organization Unique Identifier (OUI)identifying the organization which is responsible for this encapsulationand one following octet used to identify the encapsulation methoddefined by that organization. Always set equal toaDrniEncapsulationMethod. A value of 1 indicates that Network/IPLsharing by time is used. A value of 2 indicates that the encapsulationmethod used is the same as the one used by network frames and thatNetwork/IPL sharing by tag is used. Table below provides the IEEE OUI(01-80-C2) encapsulation method encodings.

TABLE 7 IEEE Encapsulation methods Encapsulation Method Field Value IPLis using a separate physical or 0 Aggregation link Network/IPL sharingby time 1 Network/IPL sharing by tag 2 IEEE802.1Q I-TAG based 3encapsulation IEEE802.1Q B-VLAN based 4 encapsulation IETF Pseudowirebased encapsulation 5 Reserved 6-255

Network/IPL Sharing Encapsulation TLV

The Network/IPL Sharing Encapsulation TLV structure may be as shownbelow and as further described in the following field definitions.

TABLE 8 Network/IPL Sharing Encapsulation TLV Length TLV (Octets)TLV_type = Network/IPL Sharing 1 EncapsulationNetwork/IPL_Sharing_Encapsulation_ 1 Length = 34DRF_Home_Network/IPL_IPLEncap_Digest 16DRF_Home_Network/IPL_NetEncap_Digest 16

TLV_type=Network/IPL Sharing Encapsulation TLV. This field indicates thenature of the information carried in this TLV-tuple. The Network/IPLsharing TLVs is identified by the integer value 0x08.

Network/IPL_Sharing_Encapsulation_Length. This field indicates thelength (in octets) of this TLV-tuple. The Network/IPL sharing TLVs usesa length value of 34 (0x22).

DRF_Home_Network/IPL_IPLEncap_Digest. This field contains the value ofthe MD5 digest computed from aDrniIPLEncapMap for exchange with theNeighbor Portal System on the IPL.

DRF_Home_Network/IPL_NetEncap_Digest. This field contains the value ofthe MD5 digest computed from aDrniNetEncapMap for exchange on the sharednetwork link.

DrniEncapsulationMethod

ATTRIBUTE

APPROPRIATE SYNTAX

A SEQUENCE OF OCTETS consisting of an Organization Unique Identifier(OUI) and one following octet.

BEHAVIOR DEFINED AS

This managed object is applicable only when Network/IPL sharing by timeor Network/IPL sharing by tag or Network/IPL sharing by encapsulation issupported. The object identifies the value representing theencapsulation method that is used to transport IPL frames to theNeighbor Portal System when the IPL and network link are sharing thesame physical link. It consists of the three-octet Organization UniqueIdentifier (OUI) identifying the organization which is responsible forthis encapsulation and one following octet used to identify theencapsulation method defined by that organization. Table on IEEEencapsulation methods provides the IEEE OUI (01-80-C2) encapsulationmethod encodings. A Default value of 0x01-80-C2-00 indicates that theIPL is using a separate physical or Aggregation link. A value of 1indicates that Network/IPL sharing by time is used. A value of 2indicates that the encapsulation method used is the same as the one usedby network frames and that Network/IPL sharing by tag is used.

DrniIPLEncapMap

ATTRIBUTE

APPROPRIATE SYNTAX

A SEQUENCE OF INTEGERs, indexed by Gateway Conversation ID.

BEHAVIOR DEFINED AS

This managed object is applicable only when Network/IPL sharing by tagor Network/IPL sharing by encapsulation is supported. Each entryrepresents the value of the identifier used for an IPL frame associatedwith that Gateway Conversation ID for the encapsulation method specifiedherein.

aDrniNetEncapMap

ATTRIBUTE

APPROPRIATE SYNTAX

A SEQUENCE OF INTEGERs, indexed by Gateway Conversation ID.

BEHAVIOR DEFINED AS

This managed object is applicable only when Network/IPL sharing by tagis supported. Each entry represents the translated value of theidentifier used for a network frame associated with that GatewayConversation ID when the method specified herein is the Network/IPLsharing by tag method specified herein and the network frames need toshare the tag space used by IPL frames.

aAggPortAlgorithm

ATTRIBUTE

APPROPRIATE SYNTAX

A SEQUENCE OF OCTETS consisting of a three-octet Organization UniqueIdentifier (OUI) and one following octet.

BEHAVIOR DEFINED AS

This object identifies the algorithm used by the Aggregator to assignframes to a Port Conversation ID.

aAggActorSystemID

ATTRIBUTE

APPROPRIATE SYNTAX:

MACAddress

BEHAVIOUR DEFINED AS:

A 6-octet read-write MAC address value used as a unique identifier forthe System that contains this Aggregator.

NOTE—From the perspective of the Link Aggregation mechanisms describedin Clause 6, only a single combination of Actor's System ID and SystemPriority are considered, and no distinction is made between the valuesof these parameters for an Aggregator and the Aggregation Port(s) thatare associated with it (i.e., the protocol is described in terms of theoperation of aggregation within a single System). However, the managedobjects provided for the Aggregator and the Aggregation Port both allowmanagement of these parameters. The result of this is to permit a singlepiece of equipment to be configured by management to contain more thanone System from the point of view of the operation of Link Aggregation.This may be of particular use in the configuration of equipment that haslimited aggregation capability.

aAggActorSystemPriority

ATTRIBUTE

APPROPRIATE SYNTAX:

INTEGER

BEHAVIOUR DEFINED AS:

A 2-octet read-write value indicating the priority value associated withthe Actor's System ID.

Organization-Specific TLV

Any organization can define TLVs for use in DRCP. These TLVs areprovided to allow different organizations, such as IEEE 802.1, ITU-T,IETF, as well as individual software and equipment vendors, to defineTLVs that advertise information to Neighbor Portal Systems. TheOrganization-Specific TLV structure shall be as shown in table below andas further described in the following field definitions.

TLV_type = Organization-Specific 1 Organization_Specific_Length = LL 1OUI 3 Subtype 7 Value (Optional) LL-12,,,,,

TLV_type=Organization-Specific TLV. This field indicates the nature ofthe information carried in this TLV-tuple. The Organization-Specific TLVis identified by the integer value 0x0F.

Network/IPL_Sharing_Encapsulation_Length. This field indicates thelength (in octets) of this TLV-tuple. The Organization-Specific TLV usesa length value of LL.

OUI. This field contains the 3-byte long Organizationally UniqueIdentifier, obtainable from IEEE.

Subtype. This field contains a Subtype value, so that an additional OUIwill not be required if more Organization-Specific TLVs are required byan owner of an OUI.

Value. This field contains the information that needs to be communicatedto the Neighbor Portal Systems.

DRCP State Machine Overview

The operation of the protocol is controlled by a number of statemachines, each of which performs a distinct function. These statemachines are for the most part described on a per-IPP basis; anydeviations from per-Aggregation Port description are highlighted in thetext. Events (such as expiration of a timer or received DRCPDUs) maycause state transitions and also cause actions to be taken; thoseactions may include the need for transmission of a DRCPDU containingrepeated or new information. Periodic and event-driven transmissions arecontrolled by the state of a Need-To-Transmit (NTT) variable, generatedby the state machines as necessary.

The state machines are as follows:

A) Receive machine (see FIG. 8). This state machine receives DRCPDUsfrom the Neighbor Portal System on this IPP, records the informationcontained, and times it out using either Short Timeouts or LongTimeouts, according to the setting of DRCP_Timeout. It evaluates theincoming information from the Neighbor Portal System to determinewhether the Home and Neighbor have both agreed upon the protocolinformation exchanged to the extent that the Home Portal System can nowbe safely used, either in Portal with other Portal Systems or as anindividual Portal; if not, it asserts NTT in order to transmit freshprotocol information to the Neighbor Portal System. If the protocolinformation from the Neighbor Portal Systems times out, the Receivemachine installs default parameter values for use by the other statemachines.

B) Periodic Transmission machine (PTS—see FIG. 9). This state machinedetermines the period that the Home Portal System and its Neighbors willexchange DRCPDUs in order to maintain the Portal.

C) Portal System machine (PS—see FIG. 10). This state machine isresponsible to update the operational status of all the Gateways andAggregation Ports in the Portal based on local information and DRCPDUsreceived on the Home Portal System's IPPs. This state machine is perPortal System.

D) DRNI Gateway and Aggregator machines (DGA—see FIG. 11). These statemachines are responsible for configuring the Gateway Conversation IDswhich are allowed to pass through this DR function's Gateway and thePort Conversation IDs which are allowed to be distributed through thisDR function's Aggregator. These state machine are per Portal System.

E) DRNI IPP machine (IPP—see FIG. 12). These state machines areresponsible for configuring the Gateway Conversation IDs and the PortConversation IDs which are allowed to pass through this DR Function'sIPPs.

F) Transmit machine (TX—see subsection Transmit machine herein below).This state machine handles the transmission of DRCPDUs, both on demandfrom the other state machines, and on a periodic basis.

FIG. 7 illustrates the relationships among these state machines and theflow of information between them according to one embodiment of theinvention. The set of arrows labeled Neighbor State Informationrepresents new Neighbor information, contained in an incoming DRCPDU orsupplied by administrative default values, being fed to each statemachine by the Receive machine. The set of arrows labeled Home StateInformation represents the flow of updated Home state informationbetween the state machines. Transmission of DRCPDUs occurs either as aresult of the Periodic machine determining the need to transmit aperiodic DRCPDU, or as a result of changes to the Home's stateinformation that need to be communicated to the Neighbors. The need totransmit a DRCPDU is signaled to the Transmit machine by asserting NTT.The remaining arrows represent shared variables in the state machinedescription that allow a state machine to cause events to occur inanother state machine.

FIG. 15 illustrates the relationships among these state machines and theflow of information between them according to another embodiment of theinvention. The alternate embodiment operates in a similar fashionaccording the principles and structures described herein and illustratedin the diagram of FIG. 15. Thus, the description generally applies toboth embodiments except where noted.

These state machines utilize a set of constants, variables, messages andfunctions as detailed herein below.

Management for Distributed Resilient Network Interconnect

Distributed Relay Attributes

aDrniPortalId

ATTRIBUTE

APPROPRIATE SYNTAX: A SEQUENCE OF 8 OCTETS that match the syntax of a48-bit MAC Address

BEHAVIOUR DEFINED AS: A read-write identifier of a particular Portal.aDrniPortalId has to be unique among at least all of the potentialPortal Systems to which a given Portal System might be attached via anIPL. Also used as the Actor's System ID for the emulated system.

DrniDescription

ATTRIBUTE

APPROPRIATE SYNTAX:

A PrintableString, 255 characters max.

BEHAVIOUR DEFINED AS:

A human-readable text string containing information about the DistributeRelay. This string is read-only. The contents are vendor specific.

aDrniName

ATTRIBUTE

APPROPRIATE SYNTAX:

A PrintableString, 255 characters max.

BEHAVIOUR DEFINED AS:

A human-readable text string containing a locally significant name forthe Distributed Relay. This string is read-write.

aDrniPortalAddr

ATTRIBUTE

APPROPRIATE SYNTAX:

A SEQUENCE OF 6 OCTETS that match the syntax of a 48-bit MAC Address

BEHAVIOUR DEFINED AS:

A read-write identifier of a particular Portal. aDrniPortalAddr has tobe unique among at least all of the potential Portal Systems to which agiven Portal System might be attached via an IPL. Also used as theActor's System ID (6.3.2) for the emulated system.

aDrniPortalPriority

ATTRIBUTE

APPROPRIATE SYNTAX: INTEGER

BEHAVIOUR DEFINED AS: A 2-octet read-write value indicating the priorityvalue associated with the Portal's ID. Also used as the Actor's SystemPriority for the emulated system.

aDrniPortalTopology

ATTRIBUTE

APPROPRIATE SYNTAX:

INTEGER

BEHAVIOUR DEFINED AS:

A read-write value indicating the Portal's topology. Value 3 stands fora Portal of three Portal Systems connected in a ring by threeIntra-Portal Links, Value 2 stands for a Portal of three Portal Systemsconnected in a chain by two IPLs, Value 1 stands for a Portal of twoPortal Systems connected by a single IPL and Value 0 stands for a Portalof a single Portal System with no active IPLs. The default value is 1.

aDrniPortalSystemNumber

ATTRIBUTE

APPROPRIATE SYNTAX: A Portal System Number, which is an integer in therange 1 through 3 inclusive.

BEHAVIOR DEFINED AS: A read-write identifier of this particular PortalSystem within a Portal. Must be unique among the Portal Systems with thesame aDrniPortalId.

aDrnilntraPortalLinkList

ATTRIBUTE

APPROPRIATE SYNTAX: A SEQUENCE OF INTEGERs that match the syntax of anInterface Identifier.

BEHAVIOR DEFINED AS: Read-write list of the Intra-Portal Links assignedto this Distributed Relay. The Port Number of each IPL is configured tomuch the Portal System Number of the attached Portal System.

aDrniLoopBreakLink

ATTRIBUTE

APPROPRIATE SYNTAX

An INTEGER that match the syntax of an Interface Identifier.

BEHAVIOR DEFINED AS

A read-write identifier that matches one of the Interface Identifiers ofthe aDrnilntraPortalLinkList. Its value identifies the interface (“LoopBreak Link”) that needs to break the data loop, in the case of a Portalof three Portal Systems connected in a ring, when all the IPLs areoperational. This managed object is only used when the value inaDrniPortalTopology is 3.

aDrniAggregator

ATTRIBUTE

APPROPRIATE SYNTAX: An INTEGER that matches the syntax of an InterfaceIdentifier.

BEHAVIOR DEFINED AS: Read-write Interface Identifier of the AggregatorPort assigned to this Distributed Relay.

aDrniConvAdminGateway[ ]

ATTRIBUTE

APPROPRIATE SYNTAX: An array of SEQUENCE OF INTEGERs that match thesyntax of Portal System Number.

BEHAVIOR DEFINED AS: There are 4096 aDmiConvAdminGateway[ ] variables,aDrniConvAdminGateway[0] through aDrniConvAdminGateway[4095], indexed byGateway Conversation ID. Each contains the current administrative valueof the Gateway selection priority list for the Distributed Relay. Thisselection priority list, a sequence of integers for each GatewayConversation ID, is a list of Portal System Numbers in the order ofpreference, highest to lowest, for the corresponding preferred PortalSystem's Gateway to carry that Conversation.

NOTE—To the extent that the network administrator fails to configure thesame values for the aDmiConvAdminGateway variables in all of the DRFunctions of a Portal, frames can be misdirected. The Distributed RelayControl Protocol (DRCP, 9.4) prevents against such type ofmisconfigurations.

aDrniGatewayAlgorithm

ATTRIBUTE

APPROPRIATE SYNTAX: A SEQUENCE OF OCTETS consisting of an OrganizationUnique Identifier (OUI) and one or more following octets.

BEHAVIOR DEFINED AS: This object identifies the algorithm used by the DRFunction to assign frames to a Gateway Conversation ID.

Constants

The following discussion focuses on a variety of constants applicableaccording to one embodiment of the invention. All timers specified inthis section have an implementation tolerance of ±250 ms.

Fast_Periodic_Time: The number of seconds between periodic transmissionsusing Short Timeouts.

Value: Integer; 1

Slow_Periodic_Time: The number of seconds between periodic transmissionsusing Long Timeouts.

Value: Integer; 30

Short_Timeout_Time: The number of seconds before invalidating receivedLACPDU information when using Short Timeouts (3×Fast_Periodic_Time).

Value: Integer; 3

Long_Timeout_Time: The number of seconds before invalidating receivedLACPDU information when using Long Timeouts (3×Slow_Periodic_Time).

Value: Integer; 90

Aggregate_Wait_Time: The number of seconds to delay aggregation, toallow multiple links to aggregate simultaneously.

Value: Integer; 2

Variables associated with the Distributed Relay

The following discussion focuses on a variety of variables associatedwith the distributed relays according to one embodiment of theinvention.

Drni_Aggregator_Priority: The System Priority of the Aggregatorassociated to this Portal. Always set equal to aAggActorSystemPriority.Transmitted in DRCPDUs.

Value: Integer; Assigned by administrator or System policy.

Drni_Aggregator_ID: The MAC address component of the System Identifierof the Aggregator associated with this Portal. Always set equal toaAggActorSystemID and it is transmitted in DRCPDUs.

Value: 48 bits

Drni_Gateway_Conversation: Operational vector listing which PortalSystem's Gateway (if any) is passing each Gateway Conversation ID.

Value: sequence of Portal System Numbers (0 for none), indexed byGateway Conversation ID.

Value computed from aDmiConvAdminGateway[ ] andDrni_Portal_System_State[ ] upon initialization and whenever the managedobject or variable changes.

Drni_Port_Conversation: Operational vector listing which Portal System(if any) is passing each Port Conversation ID.

Value: sequence of Portal System Numbers (0 for none), indexed by PortConversation ID.

Value computed from aAggConversationAdminPort[ ] andDrni_Portal_System_State[ ] upon initialization and whenever the managedobject or variable changes.

Drni_Portal_Priority: The System Priority of the Portal. Always setequal to aDrniPortalPriority. Transmitted in DRCPDUs.

Value: Integer

Assigned by administrator or System policy.

Drni_PortalID (or Drni_Portal_Addr in some embodiment): The MAC addresscomponent of the System Identifier of the Portal. Always set equal toaDrniPortalId. Transmitted in DRCPDUs.

Value: 48 bits

Assigned by administrator or System policy.

Drni_Portal_Topology: The Portal's configured topology. Always set equalto aDrniPortalTopology. Transmitted in DRCPDUs.

Value: An integer in the range [0 . . . 3]

Assigned by administrator or System policy.

Per-DR Function Variables

ChangeDRFPorts: This variable tracks the operational state of theGateway and all Aggregation Ports associated to this Portal System andis set to TRUE when any of them changes. This variable can also be setto TRUE if new values for the Drni_Conversation_GatewayList[ ] orDrni_Conversation_PortList[ ] are initiated.

Value: Boolean

ChangePortal: This variable is set to TRUE when theDRF_Neighbor_Oper_DRCP_State.IPP_Activity on any IPP on this PortalSystem changes.

Drni_Conversation_GatewayList[ ]: An array of 4096 lists, indexed byGateway Conversation ID, that determines which Gateway in this Portalcarries which Gateway Conversation ID. Each item in the array is a listof Gateways in this Portal, in priority order from most desired to leastdesired, for carrying the indexed Gateway Conversation ID. Assigned byadministrator or system policy. Always set equal toaDmiConvAdminGateway[ ].

Drni_Conversation_PortList[ ]: An array of 4096 lists, indexed by PortConversation ID, that determines which Aggregation Port in this Portalcarries which Port Conversation ID. Each item in the array is a list ofAggregation Ports in this Portal, in priority order from most desired toleast desired, for carrying the indexed Port Conversation ID. Assignedby administrator or system policy. Always set equal toaAggConversationAdminPort[ ].

Value: sequence of Port IDs

Drni_Portal_System_State[ ]: The states of all Portal Systems in thisPortal, indexed by Portal System Number.

Value: Boolean flag indication operation state of Gateway (TRUEindicates operational), a List (perhaps empty) of the Port IDs of theoperational Aggregation Ports in that Portal System, and the identity ofthe IPP, if any, from which the Portal System's state was obtained. Thisvariable is set by the updatePortalState function. Transmitted inDRCPDUs.

DRF_Home_Admin_Aggregator_Key: The administrative Aggregator Key valueassociated with this Portal System's Aggregator. Transmitted in DRCPDUs.

Value: Integer

In one embodiment, DRF_Home_Admin_Aggregator_Key is assigned byadministrator or System policy. The DRF_Home_Admin_Aggregator_Key isconfigured and must be different for each Portal System. Specificallythe two most significant bits must be different in each Portal System.The lower 14 bits may be any value, do not need to be the same in eachPortal System, and have a default of zero.

Assigned by administrator or System policy.

DRF_Home_Conversation_GatewayList_Digest: A digest ofaDrniConvAdminGateway[ ], configured in this DR Function, for exchangewith the Neighbor Portal Systems. This variable is referenced by theDRCPDU.

Value: MD5 digest

DRF_Home_Conversation_PortList_Digest: A digest ofaAggConversationAdminPort[ ], configured in this DR Function, forexchange with the Neighbor Portal Systems. Transmitted in DRCPDUs.

Value: MD5 digest

DRF_Home_Gateway_Algorithm: The gateway algorithm used by this DRFunction to assign frames to Gateway Conversation IDs. Always set equalto the aDrniGatewayAlgorithm. Transmitted in DRCPDUs.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Home_Port_Algorithm: The port algorithm used by this DR Function toassign frames to Port Conversation IDs. Always set equal to theassociated Aggregator's aAggPortAlgorithm. Transmitted in DRCPDUs.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Home_Oper_Aggregator_Key: The operational Aggregator Key valueassociated with this Portal System's Aggregator. Its value is computedby the updateKey function. Transmitted in DRCPDUs.

Value: Integer

DRF_Home_Oper_Partner_Aggregator_Key: The operational Partner AggregatorKey associated with this Portal System's Aggregator LAG ID. Transmittedin DRCPDUs.

Value: Integer

DRF_Home_State: The operational state of this DR Function. Transmittedin DRCPDUs.

Value: Boolean flag indication operation state of this Portal System'sGateway (TRUE indicates operational) and a List (perhaps empty) of thePort IDs of the operational Aggregation Ports in this Portal System.

DRF_Neighbor_Admin_Conversation_GatewayList_Digest: The value for theAlgorithm of the Neighbor Portal System, assigned by administrator orSystem policy for use when the Neighbor's information is unknown. Itsdefault value is the MD5 digest computed from aDrniConvAdminGateway[ ].

Value: MD5 digest

DRF_Neighbor_Admin_Conversation_PortList_Digest: The value for theAlgorithm of the Neighbor Portal System, assigned by administrator orSystem policy for use when the Neighbor's information is unknown. Itsdefault value is the MD5 digest computed from aAggConversationAdminPort[].

Value: MD5 digest

DRF_Neighbor_Admin_Gateway_Algorithm: The value for the gatewayalgorithm of the Neighbor Systems, assigned by administrator or Systempolicy for use when the Neighbor's information is unknown. Its defaultvalue is set equal to aDrniGatewayAlgorithm.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Neighbor_Admin_DRCP_State: Default value for the Neighbor Portal'sDRCP state parameters, assigned by administrator or System policy foruse when the Partner's information is unknown or expired. The valueconsists of the following set of variables, as described one embodiment:

-   HomeGateway-   NeighborGateway-   OtherGateway-   IPPActivity-   Timeout-   GatewaySync-   PortSync-   Expired

Value: 8 bits

DRF_Neighbor_Admin_Port_Algorithm: The value for the port algorithm ofthe Neighbor Systems, assigned by administrator or System policy for usewhen the Neighbor's information is unknown. Its default value is setequal to aAggPortAlgorithm.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Portal_System_Number: A unique identifier for this Portal System inthe Portal.

Value: An integer in the range [1 . . . 3] in one embodiment.

Copied from aDrniPortalSystemNumber. Transmitted in DRCPDUs.

PSI (portal state isolated): This variable is set to TRUE by theupdateDRFHomeState function when the Portal System is isolated from theother Portal Systems within the same Portal.

Value: Boolean.

Per-IPP Variables

The following discussion focuses on a variety of variables per IPPaccording to one embodiment of the invention.

Ipp_Gateway_Conversation_Direction: Operational list of which GatewayConversation IDs are passing through Gateways reachable through thisIPP. It is set by the operation of DRCP.

Value: Vector of Boolean flags indexed by Gateway Conversation ID;TRUE=some Gateway reachable through this IPP is enabled for this GatewayConversation ID.

For each Gateway Conversation ID, the value is TRUE if and only if a)the variables Drni_Gateway_Conversation and Drni_Portal_System_State[ ]indicate that the target Portal System for this Gateway Conversation IDlies behind this IPP, and b) Drni_Gateway_Conversation andIpp_Other_Gateway_Conversation are in agreement as to which PortalSystem should get this Gateway Conversation ID.Ipp_Gateway_Conversation_Direction is initialized to FALSE andrecomputed whenever any of its contributing variables changes. Forframes received on this IPP, TRUE means that the frame is a Down frame,ultimately destined for an Aggregator (or discard), and FALSE means theframe is an Up frame, ultimately destined for a Gateway (or discard).For frames offered for transmission on this IPP, TRUE indicates that theframe can pass, and FALSE that it cannot. This variable is not used tocontrol Down frames.

Ipp_Port_Conversation_Passes: Operational list of which PortConversation IDs are allowed to be transmitted through this IPP.

Value: Vector of Boolean flags indexed by Port Conversation ID.

This variable is examined only when a Down frame is offered fortransmission on this IPP. For each Port Conversation ID, the value isTRUE (ID passes) if and only if a) the variables Drni_Port_Conversationand Drni_Portal_System_State[ ] indicate that the target Portal Systemfor this Port Conversation ID lies behind this IPP, and b)Drni_Port_Conversation and Ipp_Other_Port_Conversation_Portal_System arein agreement as to which Portal System should get this Port ConversationID. Ipp_Port_Conversation_Passes is initialized to FALSE and recomputedwhenever any of its contributing variables changes.

ChangePortal: This variable is set to TRUE when theDRF_Neighbor_Oper_DRCP_State.IppActivity on any IPP on this PortalSystem Changes.

Value: Boolean

CC_Time_Shared: A Boolean indicating that Neighbor and Home PortalSystems on this IPP are consistently configured to use Network/IPLsharing by time.

Value: Boolean

CC_EncTag_Shared: A Boolean indicating that Neighbor and Home PortalSystems on this IPP are consistently configured to use Network/IPLsharing by tag or Network/IPL sharing by encapsulation as dictated bythe Network/IPL method selected the aDrniEncapsulationMethod.

Value: Boolean

Differ_Conf_Portal: A Boolean indicating that the configured Portalparameters used by the immediate Neighbor Portal System on this IPP aredifferent from the expected ones.

Value: Boolean

Differ_Portal: A Boolean indicating that the received DRCPDU on this IPPis associated with a different Portal.

Value: Boolean

DRF_Home_Conf_Neighbor_Portal_System_Number: This Portal System'sconfiguration value for the Portal System Number of the Neighbor PortalSystem attached to this IPP. Always set equal to the value assigned tothe two least significant bits of the priority component of the Port IDof this IPP. Transmitted in DRCPDUs.

Value: An integer in the range [1 . . . 3].

DRF_Home_Loop_Break_Link: A Boolean indicating that the IPL attached tothis IPP is configured in aDrniLoopBreakLink as a Loop Break Link.Transmitted in DRCPDUs.

Value: Boolean

DRF_Home_Network/IPL_IPLEncap_Digest: A digest of aDrniIPLEncapMap,configured on this IPP, for exchange with the Neighbor Portal System onthe IPL. Transmitted in the Network/IPL Sharing Encapsulation TLV.

Value: MD5 digest

DRF_Home_Network/IPL_NetEncap_Digest: A digest of aDrniNetEncapMap,configured on this IPP, for exchange on the shared network link.Transmitted in the Network/IPL Sharing Encapsulation TLV.

Value: MD5 digest

DRF_Home_Network/IPL_Sharing_Method: The Network/IPL sharing method usedby this DR Function to share this IPP with network data. Always setequal to the aDrniEncapsulationMethod. Transmitted in the Network/IPLSharing Method TLV when the aDrniEncapsulationMethod is not set to thedefault NULL value.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for defining this method followed by one octet identifyingthis specific method).

DRF_Home_Oper_DRCP_State: The operational values of this Portal System'sDRCP state parameters as reported on this IPP. This consists of thefollowing set of variables, as described herein above:

-   HomeGateway-   NeighborGateway-   OtherGateway-   IPPActivity-   Timeout-   GatewaySync-   PortSync-   Expired

Value: 8 bits

DRF_Neighbor_Admin_Aggregator_Key: In one embodiment, it is defined asthe administrative Aggregator Key value of the Neighbor Portal System onthis IPP. Transmitted in DRCPDUs.

Value: Integer

DRF_Neighbor_Aggregator_Priority: The last received, System Priority ofthe Neighbor's Aggregator, on this IPP.

Value: Integer

DRF_Neighbor_AggregatorID: The last received, MAC address component ofAggregator System ID of the Neighbor Portal System, on this IPP.

Value: 48 bits

DRF_Neighbor_Aggregator_Priority: The last received, System Priority ofthe Neighbor Portal System's Aggregator, on this IPP.

Value: Integer

DRF_Neighbor_Conversation_GatewayList_Digest: The last-received gatewayconversation ID digest of the Neighbor Portal System on this IPP.

Value: MD5 digest

DRF_Neighbor_Conversation_PortList_Digest: The last-received PortConversation ID digest of the Neighbor Portal system on this IPP

Value: MD5 digest

DRF_Neighbor_Gateway_Algorithm: The value of the algorithm used by theNeighbor Portal System to assign frames to Gateway Conversation IDsreceived on this IPP.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Neighbor_Loop_Break_Link: A Boolean indicating that the IPL attachedto this IPP is identified by the Neighbor Portal System on this IPP as aLoop Break Link.

Value: Boolean

DRF_Neighbor_Network/IPL_IPLEncap_Digest: The last-received digest ofaDrniIPLEncapMap of the Neighbor Portal System on this IPP.

Value: MD5 digest

DRF_Neighbor_Network/IPL_NetEncap_Digest: The last-received digest ofaDrniNetEncapMap, for exchange on the shared network link of theNeighbor Portal System on this IPP.

Value: MD5 digest

DRF_Neighbor_Network/IPL_Sharing_Method: The last-received Network/IPLsharing method used of the Neighbor Portal System on this IPP.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for defining this method followed by one octet identifyingthis specific method).

DRF_Neighbor_Oper_Aggregator_Key: The last-received operationalAggregator Key value of the Neighbor Portal System on this IPP.

Value: Integer

DRF_Neighbor_Oper_Partner_Aggregator_Key: The operational PartnerAggregator Key value of the Neighbor Portal System on this IPP.Transmitted in DRCPDUs.

Value: Integer

DRF_Neighbor_Oper_DRCP_State: The operational value of this PortalSystem's view of the current values of the Neighbor's DRCP stateparameters. The Home DR Function sets this variable either to the valuereceived from the Neighbor Portal System in an DRCPDU. The valueconsists of the following set of variables, as described herein above:

-   HomeGateway-   NeighborGateway-   OtherGateway-   IPPActivity-   Timeout-   GatewaySync-   PortSync-   Expired

Value: 8 bits

DRF_Neighbor_Conf_Portal_System_Number: The Neighbor Portal System'sconfiguration Portal System Number value for this Portal System that waslast received on this IPP.

Value: An integer in the range [1 . . . 3].

DRF_Neighbor_Port_Algorithm: The value of the algorithm used by theNeighbor Portal System to assign frames to Port Conversation IDsreceived on this IPP.

Value: 4-octet (3-octet OUI identifying the organization that isresponsible for setting this algorithm followed by two octetsidentifying this specific algorithm). In another embodiment, 5 octetsare used.

DRF_Neighbor_Portal_System_Number: The last received identifier of theNeighbor Portal System on this IPP.

Value: An integer in the range [1 . . . 3].

DRF_Neighbor_Portal_Topology: The last received identifier of theNeighbor's Portal Topology on this IPP.

Value: An integer in the range [0 . . . 3].

DRF_Neighbor_State: The operational state of the immediate NeighborPortal System on this IPP.

Value: Boolean flag indicating the operational state of the NeighborPortal System's Gateway (TRUE indicates operational) and a List (perhapsempty) of the Port IDs of the operational Aggregation Ports on this IPP.

Drni_Neighbor_ONN

The last received ONN flag of the Neighbor Portal System on this IPPcarried within the Topology State field.

Value: Integer

DRF_Other_Neighbor_Admin_Aggregator_Key: The administrative AggregatorKey value of the other neighbor Portal System associated this IPP.Transmitted in DRCPDUs.

Value: Integer

DRF_Other_Neighbor_Oper_Partner_Aggregator_Key: The operational PartnerAggregator Key value of the other neighbor Portal System associated thisIPP. Transmitted in DRCPDUs.

Value: Integer

DRF_Other_Neighbor_State: The operational state of the other neighborPortal System on this IPP.

Value: Boolean flag indicating the operational state of the otherneighbor Portal System's Gateway (TRUE indicates operational) and a List(perhaps empty) of the Port IDs of the operational Aggregation Ports onthis IPP.

Drni_Neighbor_Portal_Addr: The last received MAC address component ofPortal's System ID of the Neighbor Portal System on this IPP.

Value: 48 bits

Drni_Neighbor_Portal_Priority: The last received System Priority of theNeighbor Portal system on this IPP.

Value: Integer

Drni_Neighbor_PortalID: The last received MAC address component ofPortal System ID of the Neighbor Portal System on this IPP.

Value: 48 bits

Drni_Neighbor_State[ ]: The last received operational value ofDrni_Portal_System_State[ ] used by the Neighbor Portal System on thisIPP.

Value: For each Portal System, Boolean flag indicating the operationalstate of the current Portal System's Gateway (TRUE indicatesoperational) and a List (perhaps empty) of the Port IDs of theoperational Aggregation Ports in this Portal System as reported by theNeighbor Portal System on this IPP.

Enabled_Time_Shared: A Boolean indicating that Neighbor and Home PortalSystem on this IPP are consistently configured and the Network/IPLsharing by time methods specified herein are enabled.

Value: Boolean

Enabled_EncTag_Shared: A Boolean indicating that Neighbor and HomePortal System on this IPP are consistently configured to use the tagmanipulation methods of Network/IPL sharing by tag or Network/IPLsharing by encapsulation, as dictated by the Network/IPL method,selected by the aDrniEncapsulationMethod.

Value: Boolean

Ipp_Other_Gateway_Conversation: The operational vector listing whichPortal System's Gateway (if any) is passing each Gateway Conversation IDas reported by the immediate Neighbor on this IPP.

Value: sequence of Portal System Numbers (0 for none), indexed byGateway Conversation ID. Value computed from aDrniConvAdminGateway[ ]and DRF_Neighbor_State[ ] upon initialization and whenever the managedobject changes or GatewayConversationUpdate is FALSE.

Ipp_Other_Port_Conversation_Portal_System: The operational vectorlisting which Portal System (if any) is passing each Port ConversationID as reported by the immediate Neighbor on this IPP.

Value: sequence of Portal System Numbers (0 for none), indexed by PortConversation ID. Value computed from aAggConversationAdminPort[ ] andDRF_Neighbor_State[ ] upon initialization and whenever the managedobject changes or PortConversationUpdate is FALSE.

IPP_port_enabled: A variable indicating that the link has beenestablished and the IPP is operable.

Value: Boolean

TRUE if the IPP is operable (MAC_Operational==TRUE).

FALSE otherwise.

NOTE—The means by which the value of the IPP_port_enabled variable isgenerated by the underlying MAC is implementation-dependent.

Ipp_Portal_System_State[ ]: The List of the states of the Portal Systemsreachable through this IPP that was last received in a DRCPDU from thisIPP. This variable is updated by the updatePortalSystem function.

Value: For each Portal System, Boolean flag indicating the operationalstate of the current Portal System's Gateway reachable through this IPP(TRUE indicates operational) and a List (perhaps empty) of the Port IDsof the operational Aggregation Ports in that Portal System.

In this list, the state of the immediately adjacent Portal System is thefirst state in the list. The list can have at most two Portal System'sstates.

NTTDRCPDU: TRUE indicates that there is new protocol information thatshould be transmitted on this IPP, or that the Neighbor Portal Systemneeds to be reminded of the old information. FALSE is used otherwise.

ONN

Other Non Neighbor flag. This value is updated by the updatePortalStatefunction and is applicable only on Portals consisting of three PortalSystems. Transmitted in DRCPDUs.

Value: Boolean

TRUE indicates that the Other Ports Information TLV is not associatedwith an immediate Neighbor of this Portal System. FALSE (encoded as 0)indicates that the Other Ports Information TLV is an immediate Neighboron the other IPP on this Portal System.

DRCP_current_while_timer

This timer is used to detect whether received protocol information hasexpired. If DRF_Home_Oper_DRCP_State.DRCP_Timeout is set to ShortTimeout, the timer is started with the value Short_Timeout_Time.Otherwise, it is started with the value Long_Timeout_Time.

DRCP_periodic_timer (time_value)

This timer is used to generate periodic transmissions. It is startedusing the value Slow_Periodic_Time or Fast_Periodic_Time, as specifiedin the Periodic Transmission state machine.

Constants

All timers specified in this subclause have an implementation toleranceof ±250 ms.

Drni_Fast_Periodic_Time

The number of seconds between periodic transmissions using ShortTimeouts.

Value: Integer

1

Drni_Slow_Periodic_Time

The number of seconds between periodic transmissions using LongTimeouts.

Value: Integer

30

Drni_Short_Timeout_Time

The number of seconds before invalidating received DRCPDU informationwhen using Short Timeouts (3×Fast_Periodic_Time).

Value: Integer

3

Drni_Long_Timeout_Time

The number of seconds before invalidating received DRCPDU informationwhen using Long Timeouts (3×Slow_Periodic_Time).

Value: Integer

90

Variables Used for Managing the Operation of the State Machines

The following discussion focuses on a variety of Variables used formanaging the operation of the state machines according to one embodimentof the invention.

BEGIN: This variable indicates the initialization (or reinitialization)of the DRCP protocol entity. It is set to TRUE when the System isinitialized or reinitialized, and is set to FALSE when(re-)initialization has completed.

Value: Boolean

DRCP_Enabled

This variable indicates that the associated IPP is operating the DRCP.If the link is not a point-to-point link, the value of DRCP_Enabledshall be FALSE. Otherwise, the value of DRCP_Enabled shall be TRUE.

Value: Boolean

GatewayConversationUpdate: This variable indicates that the per GatewayConversation ID distributions need to be updated.

Value: Boolean

IppGatewayAllUpdate: This variable is the logical OR of theIppGatewayUpdate variables for all IPPs on this Portal System.

Value: Boolean

IppGatewayUpdate: This variable indicates that the per GatewayConversation ID distributions on the associated IPP need to be updated.There is one IppGatewayUpdate variable per IPP on this Portal System.

Value: Boolean

IppPortAllUpdate: This variable is the logical OR of the IppPortUpdatevariables for all IPPs in this Portal System.

Value: Boolean

IppPortUpdate: This variable indicates that the per Port Conversation IDdistributions on the associated IPP need to be updated. There is oneIppPortUpdate variable per IPP on this Portal System.

Value: Boolean

PortConversationUpdate: This variable indicates that the per PortConversation ID distributions need to be updated.

Value: Boolean

Functions

The following discussion focuses on a variety of functions according toone embodiment of the invention.

extractGatewayConversationID

This function extracts a Gateway Conversation ID value by applying theGateway Algorithm to the values of the parameters of the serviceprimitive that is invoked on the DR Function's Relay entity on receiptof an ISS primitive at one of the DR Function's port. The relationshipof the parameter values on the ISS primitives and the service primitiveson the DR Function's Relay entity ports is provided by the associatedsupporting functions on those ports and their configuration.

NOTE—These supporting functions can be as simple as the EISS supportingfunctions specified in 6.9 of IEEE Std 802.1Q-2011, for the case of aDRNI supported on a Customer Network Port or a Provider Network Port ona Provider Bridge (Clause 15 in IEEE Std 802.1Q), or more complex, likethe EISS supporting functions specified in 6.10 or 6.11 in IEEE Std802.1Q-2011, for the case of DRNI supported on a Provider Instance Portor a Customer Backbone Port respectively on a Backbone Edge Bridge(Clause 16 in IEEE Std 802.1Q) or, like the C-tagged Service Interfacesupporting functions or the Remote Customer Service Interface supportingfunctions specified in 15.4 or 15.6 in IEEE Std 802.1Q-2013 for the caseof DRNI supported on a Customer Edge Port or a Remote Access Portrespectively on a Provider Edge Bridge.

Value: Integer in the range of 0 through 4095.

extractPortConversationID

extractPortConversationID

This function extracts a Port Conversation ID value by applying the PortAlgorithm to the values of the parameters of the service primitive thatis invoked on the Aggregator on receipt of a ISS primitive at one of theother DR Function's port. The relationship of the parameter values onthe ISS primitives on the Aggregator and the corresponding serviceprimitives on the DR Function's port is provided by the associatedsupporting function on the Aggregator and the DR Function port and theirconfigurations. Check the NOTE above.

Value: Integer in the range of 0 through 4095.

InitializeDRNIGatewayConversation

This function sets the Drni_Portal_System_Gateway_Conversation to asequence of zeroes, indexed by Gateway Conversation ID.

InitializeDRNIPortConversation

This function sets the Drni_Portal_System_Port_Conversation to asequence of zeros, indexed by Port Conversation ID.

InitializeIPPGatewayConversation

This function sets the Ipp_Gateway_Conversation_Direction to a sequenceof zeros, indexed by Gateway Conversation ID.

InitializeIPPPortConversation

This function sets the Ipp_Port_Conversation_Passes to a sequence ofzeros, indexed by Port Conversation ID.

recordDefaultDRCPDU

This function sets the default parameter values for the Neighbor PortalSystem on the IPP, provided by the administrator, to the currentNeighbor Portal System's operational parameter values as follows:

-   DRF_Neighbor_Port_Algorithm=DRF_Neighbor_Admin_Port_Algorithm;-   DRF_Neighbor_Gateway_Algorithm=DRF_Neighbor_Admin_Gateway_Algorithm;-   DRF_Neighbor_Conversation_PortList_Digest-   =DRF_Neighbor_Admin_Conversation_PortList_Digest;-   DRF_Neighbor_Conversation_GatewayList_Digest-   =DRF_Neighbor_Admin_Conversation_GatewayList_Digest;-   DRF_Neighbor_Oper_DRCP_State=DRF_Neighbor_Admin_DRCP_State;-   DRF_Neighbor_Aggregator_Priority=aAggPortPartnerAdminSystemPriority;-   DRF_Neighbor_Aggregator_ID=aAggPortPartnerAdminSystemID;-   Drni_Neighbor_Portal_Priority=aAggPortPartnerAdminSystemPriority;-   Drni_Neighbor_Portal_Addr=aAggPortPartnerAdminSystemID;-   DRF_Neighbor_Portal_System_Number-   =DRF_Home_Conf_Neighbor_Portal_System_Number;-   DRF_Neighbor_Portal_Topology=Drni_Portal_Topology;-   DRF_Neighbor_Loop_Break_Link=DRF_Home_Loop_Break_Link, and;-   DRF_Neighbor_Conf_Portal_System_Number=DRF_Portal_System_Number.

In Addition for the Neighbor Portal System on the IPP:

-   The DRF_Neighbor_State is set to NULL (the Boolean flag for the    Neighbor Portal System's Gateway is set to FALSE and the list of the    operational Aggregation Ports on the Neighbor Portal System on this    IPP is emptied) and if aDrniPortalTopology is configured to contain    three Portal Systems, the DRF_Other_Neighbor_State is also set to    NULL (the Boolean flag for the Other neighbor Portal System's    Gateway is set to FALSE and the list of the operational Aggregation    Ports on the Other neighbor Portal System on this IPP is empire). No    Portal System state information is available for any Portal System    on this IPP;-   The DRF_Neighbor_Admin_Aggregator_Key on this IPP is set to zero;-   The DRF_Other_Neighbor_Admin_Aggregator_Key on this IPP is set to    zero;-   The DRF_Neighbor_Oper_Partner_Aggregator_Key on this IPP is set to    zero;-   The DRF_Other_Neighbor_Oper_Partner_Aggregator_Key on this IPP is    set to zero, and;-   The variable ChangePortal is set to TRUE.

Finally it sets CC_Time_Shared and CC_EncTag_Shared to FALSE.

recordNeighborState

This function records the parameter values for theDrni_Portal_System_State[ ] and DRF_Home_Oper_DRCP_State carried in areceived DRCPDU on the IPP, as the current parameter values forDrni_Neighbor_State[ ] and DRF_Neighbor_Oper_DRCP_State associated withthis IPP respectively and sets DRF_Neighbor_Oper_DRCP_State.IPP_Activityto TRUE.

It also records the variables below as follows:

-   The parameter values for the Home_Gateway in the    DRF_Home_Oper_DRCP_State and the Active_Home_Ports in the Home Ports    Information TLV, carried in a received DRCPDU on the IPP, are used    as the current values for the DRF_Neighbor_State on this IPP and    associates this Portal System state information on this IPP with the    Portal System identified by DRF_Neighbor_Portal_System_Number;-   The parameter values for the Other_Gateway in the    DRF_Home_Oper_DRCP_State and the Other_Neighbor_Ports in the Other    Ports Information TLV, carried in a received DRCPDU on the IPP, are    used as the current values for the DRF_Other_Neighbor_State on this    IPP and associates this Portal System state information with the    Portal System identified by the value assigned to the two most    significant bits of the DRF_Other_Neighbor_Admin_Aggregator_Key    carried within the Other Ports Information TLV in the received    DRCPDU. If no Other Ports Information TLV is carried in the received    DRCPDU and the Portal Topology contains three Portal Systems, the    DRF_Other_Neighbor_State is set to NULL (Other_Gateway is set to    FALSE and the list of the operational Aggregation Ports on the Other    neighbor Portal System on this IPP is emptied) and no Portal System    state information is available on this IPP for the distant Neighbor    Portal System on the IPP;-   DRF_Neighbor_Admin_Aggregator_Key=DRF_Home_Admin_Aggregator_Key;-   DRF_Neighbor_Oper_Partner_Aggregator_Key=DRF_Home_Oper_Partner_Aggregator_Key;-   DRF_Other_Neighbor_Admin_Aggregator_Key=DRF_Other_Neighbor_Admin_Aggregator_Key,    and;-   DRF_Other_Neighbor_Oper_Partner_Aggregator_Key    N=DRF_Other_Neighbor_Oper_Partner_Aggregator_Key.-   Both DRF_Other_Neighbor_Admin_Aggregator_Key and    DRF_Other_Neighbor_Oper_Partner_Aggregator_Key are set to NULL when    the received DRCPDU does not contain the Other Ports Information    TLV.

In addition, if Network/IPL sharing by time is supported, the functionrecords the parameter value for the DRF_Home_Network/IPL_Sharing_Methodcarried in the received Network/IPL Sharing Method TLV as the currentparameter value for the DRF_Neighbor_Network/IPL_Sharing_Method and ifthis is the same as the System's DRF_Home_Network/IPL_Sharing_Method, itsets CC_Time_Shared to TRUE, otherwise it sets CC_Time_Shared to FALSE.

Further, if Network/IPL sharing by tag or Network/IPL sharing byencapsulation is supported, the function records the Neighbor PortalSystem's Network/IPL sharing related parameter values carried in thereceived Network/IPL sharing TLVs from an IPP, as the currentoperational parameter values for the immediate Neighbor Portal System onthis IPP as follows:

DRF_Neighbor_Network/IPL_Sharing_Method=DRF_Home_Network/IPL_Sharing_Method,carried in the received Network/IPL Sharing Method TLV;

DRF_Neighbor_Network/IPL_IPLEncap_Digest=DRF_Home_Network/IPL_IPLEncap_Digest,carried in the received Network/IPL Sharing Encapsulation TLV; and

DRF_Neighbor_Network/IPL_NetEncap_Digest=DRF_Home_Network/IPL_NetEncap_Digestcarried in the received Network/IPL Sharing Encapsulation TLV.

It then compares the newly updated values of the Neighbor Portal Systemto this Portal System's expectations and if

DRF_Neighbor_Network/IPL_Sharing_Method==DRF_Home_Network/IPL_Sharing_Method,and

DRF_Neighbor_Network/IPL_IPLEncap_Digest==DRF_Home_Network/IPL_IPLEncap_Digest,and

DRF_Neighbor_Network/IPL_NetEncap_Digest==DRF_Home_Network/IPL_NetEncap_Digest,then

it sets CC_EncTag_Shared to TRUE;

Otherwise if one or more of the comparisons shows that the valuesdiffer,

it sets CC_EncTag_Shared to FALSE.

It then compares the Gateway operational state for each Portal System asreported by this Portal System's Drni_Portal_System_State[ ] to theGateway operational state for the same Portal System as reported by theDrni_Neighbor_State[ ] and if any of these differ it setsGatewayConversationUpdate to TRUE andDRF_Home_Oper_DRCP_State.Gateway_Sync to FALSE, otherwiseGatewayConversationUpdate remains unchanged andDRF_Home_Oper_DRCP_State.Gateway_Sync is set to TRUE.

It also compares the list of the Port IDs of the operational AggregationPorts for each Portal System as reported by this Portal System'sDrni_Portal_System_State[ ] to list of the Port IDs of the operationalAggregation Ports for the same Portal Systems as reported by theDrni_Neighbor_State[ ] and if any of these differ it setsPortConversationUpdate to TRUE and DRF_Home_Oper_DRCP_State.Port_Sync toFALSE, otherwise PortConversationUpdate remains unchanged andDRF_Home_Oper_DRCP_State.Port_Sync is set to TRUE.

recordPortalConfValues

This function records the Neighbor Portal System's configured parametervalues carried in a received DRCPDU from an IPP, as the currentoperational parameter values for the immediate Neighbor Portal System onthis IPP as follows:

DRF_Neighbor_Portal_System_Number=DRF_Portal_System_Number;

DRF_Neighbor_Portal_Topology=Drni_Portal_Topology;

DRF_Neighbor_Conf_Portal_System_Number=DRF_Home_Conf_Neighbor_Portal_System_Number;

DRF_Neighbor_Loop_Break_Link=DRF_Home_Loop_Break_Link;

DRF_Neighbor_Oper_Aggregator_Key=DRF_Home_Oper_Aggregator_Key;

DRF_Neighbor_Port_Algorithm=DRF_Home_Port_Algorithm;

DRF_Neighbor_Conversation_PortList_Digest=DRF_Home_Conversation_PortList_Digest;

DRF_Neighbor_Gateway_Algorithm=DRF_Home_Gateway_Algorithm; and

DRF_Neighbor_Conversation_GatewayList_Digest=DRF_Home_Conversation_GatewayList_Digest.

It then compares the newly updated values of the Neighbor Portal Systemto this Portal System's expectations and if

DRF_Neighbor_Portal_System_Number==DRF_Home_ConfNeighbor_Portal_System_Number, and

DRF_Neighbor_Portal_Topology==Drni_Portal_Topology, and

DRF_Neighbor_Loop_Break_Link==DRF_Home_Loop_Break_Link, and

DRF_Neighbor_Conf_Portal_System_Number==DRF_Portal_System_Number, and

DRF_Neighbor_Oper_Aggregator_Key==DRF_Home_Oper_Aggregator_Key, and

DRF_Neighbor_Port_Algorithm==DRF_Home_Port_Algorithm, and

DRF_Neighbor_Conversation_PortList_Digest==DRF_Home_Conversation_PortList_Digest,and

DRF_Neighbor_Gateway_Algorithm==DRF_Home_Gateway_Algorithm, and

DRF_Neighbor_Conversation_GatewayList_Digest==DRF_Home_Conversation_GatewayList_Digestthen,

the variable Differ_Conf_Portal is set to FALSE;

Otherwise if one or more of the comparisons shows that the valuesdiffer,

the variable Differ_Conf_Portal is set to TRUE and the associated pairsof variables having the different values are available inaDrniIPPDebugDifferPortalReason.

recordPortalValues

This function records the parameter values for theDrni_Aggregator_Priority, Drni_Aggregator_ID, Drni_Portal_Priority, andDrni_PortalID, carried in a received DRCPDU from an IPP, as the currentoperational parameter values for the immediate Neighbor Portal System onthis IPP, as follows:

DRF_Neighbor_Aggregator_Priority=Drni_Aggregator_Priority;

DRF_Neighbor_Aggregator_ID=Drni_Aggregator_ID;

Drni_Neighbor_Portal_Priority=Drni_Portal_Priority, and;

Drni_Neighbor_Portal_Addr=Drni_Portal_Addr.

It then compares the newly updated values of the Neighbor Portal Systemto this Portal System's expectations and if

DRF_Neighbor_Aggregator_Priority==Drni_Aggregator_Priority and

DRF_Neighbor_Aggregator_ID==Drni_Aggregator_ID and

Drni_Neighbor_Portal_Priority==Drni_Portal_Priority and

Drni_Neighbor_Portal_Addr==Drni_Portal_Addr then,

the variable Differ_Portal is set to FALSE;

Otherwise if one or more of the comparisons shows that the valuesdiffer,

the variable Differ_Portal is set to TRUE and the associated set ofvariables having the different values are available inaDrniIPPDebugDifferPortalReason.

reportToManagement

This function alerts the Management system of the potential existence ofa Portal System configuration error in this Portal due to the receipt ofa misconfigured DRCPDU and sends to it the conflicting information fromthe misconfigured received DRCPDU.

setDefaultPortalSystemParameters

This function sets this Portal System's variables to administrative setvalues as follows:

-   Drni_Aggregator_Priority=aAggActorSystemPriority;-   Drni_Aggregator_ID=aAggActorSystemID;-   Drni_Portal_Priority=aDrniPortalPriority;-   Drni_Portal_Addr=aDrniPortalAddr;-   DRF_Portal_System_Number=aDrniPortalSystemNumber;-   DRF_Home_Admin_Aggregator_Key=aAggActorAdminKey;-   DRF_Home_Port_Algorithm=aAggPortAlgorithm;-   DRF_Home_Gateway_Algorithm=aDrniGatewayAlgorithm;-   DRF_Home_Conversation_PortList_Digest=the MD5 digest on    aDrniConvAdminGateway[ ];-   DRF_Home_Conversation_GatewayList_Digest=the MD5 digest on    aAggConversationAdminPort[ ], and;-   DRF_Home_Oper_DRCP_State=DRF_Neighbor_Admin_DRCP_State.

In addition, it sets the Drni_Portal_System_State[ ] as if all Gatewaysin the Portal are reported as FALSE and no Aggregation Port on anyPortal System is reported as operational.

setGatewayConversation

This function sets Drni_Gateway_Conversation to the values computed fromaDrniConvAdminGateway[ ] and the current Drni_Portal_System_State[ ] asfollows:

For every indexed Gateway Conversation ID, a Portal System Number isidentified by choosing the highest priority Portal System Number in thelist of Portal System Numbers provided by aDmiConvAdminGateway[ ] whenonly the operational Gateways, as provided by the Gateway Boolean flagsof the Drni_Portal_System_State[ ] variable, are included.

setlPPGatewayConversation

This function sets Ipp_Other_Gateway_Conversation to the values computedfrom aDrniConvAdminGateway[ ] and the Drni_Neighbor_State[ ] as follows:

For every indexed Gateway Conversation ID, a Portal System Number isidentified by choosing the highest priority Portal System Number in thelist of Portal System Numbers provided by aDmiConvAdminGateway[ ] whenonly the operational Gateways, as provided by the Gateway Boolean flagsof the Drni_Neighbor_State[ ] variable, are included.

setlPPGatewayUpdate

This function sets the IppGatewayUpdate on every IPP on this PortalSystem to TRUE.

setlPPPortConversation

This function sets Ipp_Other_Port_Conversation_Portal_System to thevalues computed from aAggConversationAdminPort[ ] and theDrni_Neighbor_State[ ] as follows:

For every indexed Port Conversation ID, a Portal System Number isidentified by choosing the highest priority Portal System Number in thelist of Portal Systems Numbers provided by aAggConversationAdminPort[ ]when only the operational Aggregation Ports, as provided by theassociated Lists of the Drni_Neighbor_State[ ] variable, are included.

setlPPPortUpdate

This function sets the IppPortUpdate on every IPP on this Portal Systemto TRUE.

setPortConversation

This function sets Drni_Port_Conversation to the values computed fromaAggConversationAdminPort[ ] and the current Drni_Portal_System_State[ ]as follows:

For every indexed Port Conversation ID, a Portal System Number isidentified by extracting the least significant two bits of the prioritycomponent of the highest priority Port ID (6.3.4) in the list of PortIDs provided by aAggConversationAdminPort[ ] when only the operationalAggregation Ports, as provided by the associated Lists of theDrni_Portal_System_State[ ] variable, are included.

updateDRFHomeState

This function updates the DRF_Home_State based on the operational stateof the local ports as follows:

The Gateway is set to TRUE or FALSE based on the mechanisms that areused to identify the operational state of the local Gateway (TRUEindicates operable and that

connectivity is not blocked by the operation of the network controlprotocol);

The list of operational Aggregation Ports is created by including onlythose Aggregation Port IDs for which the attached Aggregator reportsthem as having Actor_Oper_Port_State.Distributing==TRUE (condition thatexcludes the cases where the associated Aggregation Ports are either nonoperable (port_enabled=FALSE), in an EXPIRED state, or not in the LAG),and The PSI is set to TRUE ifDRF_Neighbor_Oper_DRCP_State.IPP_Activity==FALSE on all IPPs on thisPortal System, otherwise PSI is set to FALSE.

In addition, if PSI==TRUE and Gateway==FALSE thenActor_Oper_Port_State.Sync is set to FALSE on all Aggregation Ports onthis Portal System.

The function also sets:

GatewayConversationUpdate to TRUE if the operational state of Gateway orthe configured lists for Drni_Conversation_GatewayList[ ] has changedand sets PortConversationUpdate to TRUE if there has been any change inthe list of the operational Aggregation Ports as reported by changes inthe associated Actor_Oper_Port_State.Distributing variables or theconfigured lists for the Drni_Conversation_PortList[ ], otherwise;

GatewayConversationUpdate and PortConversationUpdate remain unchanged.

updatelPPGatewayConversationDirection

This function computes a value for Ipp_Gateway_Conversation_Direction asfollows:

For each Gateway Conversation ID, the value is TRUE if and only if:

a) the variables Drni_Gateway_Conversation and Ipp_Portal_System_State[] indicate that the target Portal System for this Gateway ConversationID lies behind this IPP, and

b) Drni_Gateway_Conversation and Ipp_Other_Gateway_Conversation are inagreement as to which Portal System should get this Gateway ConversationID.

In addition, if Drni_Gateway_Conversation andIpp_Other_Gateway_Conversation are in disagreement for any GatewayConversation ID:

It sets DRF_Home_Oper_DRCP_State.Gateway_Sync to FALSE, and;

NTTDRCPDU to TRUE.

Otherwise:

DRF_Home_Oper_DRCP_State.Gateway_Sync and NTTDRCPDU are left unchanged.

Ipp_Gateway_Conversation_Direction is initialized to FALSE andrecomputed whenever any of its contributing variables changes.

updatelPPPortConversationPasses

This function computes a value for Ipp_Port_Conversation_Passes asfollows:

For each Port Conversation ID, the value is TRUE (ID passes) if and onlyif:

a) the variables Drni_Port_Conversation and Ipp_Portal_System_State[ ]indicate that the target Portal System for this Port Conversation IDlies behind this IPP, and

b) Drni_Port_Conversation and Ipp_Other_Port_Conversation_Portal_Systemare in agreement as to which Portal System should get this PortConversation ID.

In addition if Drni_Port_Conversation andIpp_Other_Port_Conversation_Portal_System are in disagreement for anyPort Conversation ID:

It sets DRF_Home_Oper_DRCP_State.Port_Sync to FALSE, and;

NTTDRCPDU to TRUE.

Otherwise:

DRF_Home_Oper_DRCP_State.Port_Sync and NTTDRCPDU are left unchanged.

Ipp_Port_Conversation_Passes is initialized to FALSE and recomputedwhenever any of its contributing variables changes.

updateKey

This function updates the operational Aggregator Key,DRF_Home_Oper_Aggregator_Key, as follows:

If enable_long_pdu_xmit==TRUE then:

DRF_Home_Oper_Aggregator_Key is set to the value ofDRF_Home_Admin_Aggregator_Key by replacing its most significant two bitsby the value 01; Otherwise DRF_Home_Oper_Aggregator_Key is set to thelowest numerical non zero value of the set comprising the values of theDRF_Home_Admin_Aggregator_Key, the DRF_Neighbor_Admin_Aggregator_Key andthe DRF_Other_Neighbor_Admin_Aggregator_Key, on each IPP.

updateNTT

This function sets NTT to TRUE if any ofDRF_Home_Oper_DRCP_State.GatewaySync, orDRF_Home_Oper_DRCP_State.PortSync, orDRF_Neighbor_Oper_DRCP_State.GatewaySync, orDRF_Neighbor_Oper_DRCP_State.PortSync is FALSE.

updatePortalState

On all operations associated with this function, information provided bythe DRF_Other_Neighbor_State on an IPP is considered only ifDrni_Neighbor_ONN on the same IPP is FALSE;

This function updates the Drni_Portal_System_State[ ] as follows: Theinformation for this Portal System, DRF_Home_State, indexed by thePortal System Number, is included in Drni_Portal_System_State[ ]. Foreach of the other Portal Systems in the Portal, If any of the otherPortal System's state information is available from two IPPs in thisPortal System, then:

For that Portal System, only the Portal System state informationprovided by the DRF_Neighbor_State on the IPP having the other PortalSystem as a Neighbor Portal System, indexed by the Portal System Number,will be included in Drni_Portal_System_State[ ].

Otherwise if a Portal System's state information is available only froma single IPP on this Portal System, then:

That Portal System's state information, indexed by the associated PortalSystem Number will be included in the Drni_Portal_System_State[ ]irrespectively of whether that information is being provided by theDRF_Neighbor_State or the DRF_Other_Neighbor_State on this IPP. Ifinformation for a Portal System is available only from theDRF_Other_Neighbor_State on this IPP then ONN is set to TRUE on thisIPP.

Every Portal System included in the Portal Topology for which PortalSystem state information is not available from any of the IPPs, has itsassociated Portal System state information Drni_Portal_System_State[ ]set to NULL (the Gateway is set to FALSE and the list of the operationalAggregation Ports on the Portal System is emptied).

This function updates also the Ipp_Portal_System_State[ ] for each IPPon this Portal System as follows:

If any other Portal System's state information is available from twoIPPs, then:

If the Home Portal System that does not have any IPL configured as aLoop Break Link, then, for every IPP on the Portal System, only thePortal System state information provided by the DRF_Neighbor_State onthat IPP will be included in the associated Ipp_Portal_System_State[ ],indexed by the associated Portal System Number otherwise;

the DRF_Neighbor_State on an IPP, indexed by the associated PortalSystem Number, will be included as a first state in the correspondingIpp_Portal_System_State[ ] and any other additional state associatedwith another Portal System reported on the received DRCPDU on this IPP,indexed by the associated Portal System Number, will be included as thesecond state in the Ipp_Portal_System_State[ ] only if Drni_Neighbor_ONNon the same IPP is FALSE

[Similarly to the Drni_Portal_System_State[ ], every Portal Systemincluded in the Portal Topology for which Portal System stateinformation is not available from any of the IPPs, has its associatedPortal System state information Ipp_Portal_System_State[ ] set to NULL(the Gateway is set to FALSE and the list of the operational AggregationPorts on the Portal System is emptied).]

updatePortalSystemGatewayConversation

This function sets the Drni_Portal_System_Gateway_Conversation to theresult of the logical AND operation between, the Boolean vectorconstructed from the Drni_Gateway_Conversation, by setting to FALSE allthe indexed Gateway Conversation ID entries that are associated withother Portal Systems in the Portal, and the Boolean vector constructedfrom all IPPs Ipp_Other_Gateway_Conversation, by setting to FALSE allthe indexed Gateway Conversation ID entries that are associated withother Portal Systems in the Portal.

updatePortalSystemPortConversation

This function sets the Drni_Portal_System_Port_Conversation to theresult of the logical AND operation between, the Boolean vectorconstructed from the Drni_Port_Conversation, by setting to FALSE all theindexed Port Conversation ID entries that are associated with otherPortal Systems in the Portal, and the Boolean vector constructed fromthe Ipp_Other_Port_Conversation_Portal_System, by setting to FALSE allthe indexed Port Conversation ID entries that are associated with otherPortal Systems in the Portal.

Timers

The following discussion focuses on a variety of timers applicableaccording to one embodiment of the invention.

current_while_timer: This timer is used to detect whether receivedprotocol information has expired. If Actor_Oper_State.LACP_Timeout isset to Short Timeout, the timer is started with the valueShort_Timeout_Time. Otherwise, it is started with the valueLong_Timeout_Time.

periodic_timer (time_value): This timer is used to generate periodictransmissions. It is started using the value Slow_Periodic_Time orFast_Periodic_Time, as specified in the Periodic Transmission statemachine.

wait_while_timer: This timer provides hysteresis before performing anaggregation change, to allow all links that will join the associatedLink Aggregation Group to do so. It is started using the valueAggregate_Wait_Time.

Messages

In one embodiment, only one message is utilized:

IppM:M_UNITDATA.indication(DRCPDU): This message is generated by theDRCP Control Parser as a result of the reception of a DRCPDU.

DRCPCtrlMuxN:M_UNITDATA.indication(DRCPDU)

This message is generated by the DRCP Control Parser/Multiplexer as aresult of the reception of a DRCPDU.

Note the two messages are similar messages for two differentembodiments.

State Machine Operations

Returning to the operation of the overall state machine process, theflowchart of FIG. 7 defines a set of operations relying, in oneembodiment, to the functions, variables and messages described hereinabove. The process can be initiated in response to receiving a DRCPDU.This DRCPDU is initially passed to the receive unit (block 702). The setof arrows labeled Neighbor State Information represents new Neighborinformation, contained in an incoming DRCPDU or supplied byadministrative default values, being fed to each state machine by theDRCPDU Receive machine. The set of arrows labeled Home State Informationrepresents the flow of updated Home state information between the statemachines. Transmission of DRCPDUs occurs either as a result of thePeriodic machine determining the need to transmit a periodic DRCPDU, oras a result of changes to the Home's state information that need to becommunicated to the Neighbors. The need to transmit a DRCPDU is signaledto the Transmit machine by asserting NTTDRCPDU. The remaining arrowsrepresent shared variables in the state machine description that allow astate machine to cause events to occur in another state machine.

The Receive machine generates an NTTDRCPDU, executes a change portoperation, gateway conversation update and port conversation update.

The periodic machine 704 receives the neighbor state information andreturns home state information. The periodic machine (block 704)generates a NTTDRCPDU.

Portal System machine (block 706) is responsible to update theoperational status of all the Gateways and Aggregation Ports in thePortal based on local information and DRCPDUs received on the HomePortal System's IPPs. This state machine is per Portal System.

The DRNI Gateway and Aggregator machines (708) are responsible forconfiguring the Gateway Conversation IDs which are allowed to passthrough this DR Function's Gateway and the Port Conversation IDs whichare allowed to be distributed through this DR Function's Aggregator.These state machines are per Portal System.

The DRNI IPP machines (710) are responsible for configuring the GatewayConversation IDs and the Port Conversation IDs which are allowed to passthrough this DR Function's IPPs.

Transmit machine (712) handles the transmission of DRCPDUs, both ondemand from the other state machines, and on a periodic basis.

DRCPDU Receive Machine

The Receive machine may implement the function specified in FIG. 8 withits associated parameters as discussed herein above. The process can beinitialized block 802 when the functionality is enabled and therecordDefaultDRCPDU( ) is executed and where theDRF_Neighbor_Oper_DRCP_State.IPP_Activitiy is false. An expired state(block 804) is then entered and on receipt of a DRCPDU, the statemachine enters the PORTAL_CHECK state (block 808). TherecordPortalValues function checks if the DRCPDU is associated with thisPortal. If not, the event is reported to the management system and nofurther processing of the DRCPDU is made by any of this Portal's statemachines. If the recordPortalValues identifies the received DRCPDU willenter the COMPATIBILITY CHECK state (Block 809) to be checked by therecordPortalConfValues function. This compares the administrativelyconfigured values that are associated with this portal to the receivedinformation and if they differ the system will enter theREPORT_TO_MANAGEMENT state (Block 810) and the misconfigured DRCPDU willbe reported to the management system. The Receive machine exits theREPORT_TO_MANAGEMENT state when a new DRCPDU is received (or the IPP isdisabled).

If the received DRCPDU is configured according to the expected valuesfor this Portal the received machine will enter the CURRENT state (Block812).

Embodiments may thus comprise the steps of: receiving a DRCPDU; checkingif the received DRCPDU is associated with the portal; comparingconfigured values associated with the portal with values of the receivedDRCPDU; and sending a report in case the compared values differ.

In one embodiment, on receipt of a DRCPDU, the state machine enters thePORTAL_CHECK state. The recordPortalValues function checks if the DRCPDUis associated with this Portal. If not, the state machine will enter theREPORT_TO_MANAGEMENT state and the received DRCPDU will be reported tothe management system. While in the REPORT_TO_MANAGEMENT state, theSystem will exit to the PORTAL_CHECK state if a new DRCPDU is receivedor to the EXPIRED state if the DRCP_current_while_timer expires. If therecordPortalValues identifies the received DRCPDU as associated withthis Portal, it will enter the COMPATIBILITY_CHECK state to be checkedby the recordPortalConfValues function. This compares theadministratively configured values that are associated with this portalto the received information and if they differ the System will enter theREPORT_TO_MANAGEMENT state and the mis-configured DRCPDU will bereported to the management system. If the Portal System continues toreceive DRCPDUs that do not match the administratively configuredexpectations for a period longer than twice the Short Timeout the statemachine will transit to the DEFAULTED state and the current operationalparameters for the Portal System(s) on this IPP will be overwritten withadministratively configured values and a Portal System update will betriggered.

If the received DRCPDU is configured according to the expected valuesfor this Portal the DRCPDU Receive machine enters the CURRENT state.

The recordNeighborState function records the Neighbor's Portal Stateinformation contained in the DRCPDU in the Neighbor's Portal Stateoperational variables and update's its own Home Portal State variable.If they differ, triggers are set to notify the Neighbor but also localevent variables are set trigger updates on the local Portal Systemmachine (PS—see FIG. 10), the DRNI Gateway and Aggregator machine(DGA—see FIG. 11), and the DRNI IPP machine (IPP—see FIG. 12).

In the process of executing the recordPortalValues,recordPortalConfValues, and recordNeighborState, functions, a Receivemachine compliant to this specification may not validate the VersionNumber, TLV_type, or Reserved fields in received DRCPDUs. The sameactions are taken regardless of the values received in these fields. AReceive machine may validate the Portal_Information_Length,Portal_Configuration_Information_Length, DRCP_State_Length, orTerminator_Length fields. These behaviors, together with the constrainton future protocol enhancements, are discussed herein above.

The rules expressed above allow Version 1 devices to be compatible withfuture revisions of the protocol.

The updateNTT function is used to determine whether further protocoltransmissions are required; NTTDRCPU is set to TRUE if the Neighbor'sview of the Home's operational Portal State variable is not up to date.Then the current_while timer is started. The value used to start thetimer is either Short_Timeout_Time or Long_Timeout_Time, depending uponthe Actor's operational value of Timeout.

If no DRCPDU is received before the current_while timer expires, thestate machine transits to the EXPIRED state. TheDRF_Neighbor_Oper_DRCP_State.IPP_Activity is set to FALSE, the currentoperational value of the Neighbor's Timeout variable is set to ShortTimeout, and the current_while timer is started with a value ofShort_Timeout_Time. This is a transient state; the Timeout settingsallow the Home Portal System to transmit DRCPDUs rapidly in an attemptto re-establish communication with the Neighbor.

If no DRCPDU is received before the current_while timer expires again,the state machine transits to the DEFAULTED state. TherecordDefaultDRCPDU function overwrites the current operationalparameters for the Neighbors Portal Systems with administrativelyconfigured values and triggers a Portal System update and the conditionis reported to the management system.

If the IPP becomes inoperable, the state machine enters the INITIALIZEstate. DRF_Neighbor_Oper_DRCP_State.IPP_Activity is set to FALSE therecordDefaultDRCPDU function causes the administrative values of thePartner parameters to be used as the current operational values. Theseactions force the PS machine to detach the Neighbor Portal Systems fromthe Portal and the Gateway and Port Conversation ID filters to berecomputed.

The Receive machine may also implement the function specified in FIG. 16with its associated parameters. The receive machine in FIG. 16 follows afew different flow paths compared to FIG. 8. The terms and functions ofthe alternate receive machine in FIG. 16 are analogous to those of FIG.8. One skilled in the art would understand that other implementationsare possible consistent with the principles and structures of theillustrated receive machines.

FIG. 33 illustrates a method for synchronizing with a neighbor in a nodeof a DRNI link aggregation group according to an embodiment of theinvention. Method 3300 may be implemented on a DRCP node (e.g., anetwork device) of a DRCP portal (referred to as a local portal) as apart of a DRNI such as nodes K-O of FIG. 1B and network devices 132 and134 of FIG. 1C. Note optional steps are denoted as a dotted box asillustrated in FIG. 33.

At reference 3302, the node is initialized for operating DRCP on an IPPcoupled to a neighbor node using an IPL. The node and the neighbor nodeare included in a portal, which may contain an additional neighbor nodein one embodiment. The node is coupled to the neighbor node via the IPPusing the IPL. In one embodiment, the initialization comprises settingdefault parameter values for the neighbor node on the IPP to be thecurrent operational parameters of the neighbor node provided by anadministrator of the portal. The parameters include neighbor portalgorithm such as DRF_Neighbor_Port_Algorithm (to be set to beDRF_Neighbor_Admin_Port_Algorithm), neighbor port gateway algorithm suchas DRF_Neighbor_Gateway_Algorithm (to be set to beDRF_Neighbor_Admin_Gateway_Algorithm), and others discussed herein aboverelating to the function of recordDefaultDRCPDU. In one embodiment, theinitialization further includes setting the IPP activity of the neighbornode to be inactive through settingDRF_Neigbhor_Oper_DRCP_State.IPP_Activity to be false.

At reference 3304, the node determines that DRCP is enabled at the IPP.The checking includes determining a variable (e.g., IPP_port_enabled)indicating that the IPP is operating DRCP. In one embodiment, thedetermination is through checking two variables for the IPP. One is avariable indicating that the IPP is operating DRCP (e.g., throughDRCP_enabled discussed herein above), and the other is the variableindicating that the IPL has been established and the IPP is operable(e.g., through IPP_port_enabled discussed herein above).

At reference 3306, the node enters an expired state. In the expiredstate, the node performs the following in one embodiment: It sets thenode's DRCP state parameter to expired (e.g., settingDRF_Home_Oper_DRCP_State.Expired discussed herein above to be true), italso sets the IPP activity of the neighbor node to be inactive throughsetting DRF_Neigbhor_Oper_DRCP_State.IPP_Activity to be false. It sets atimer to expire if no DRCPDU is received. In one embodiment, the timersetting is performed through settingDRF_Neighbor_Oper_DRCP_State.DRCP_Timeout=Short Timeout and startDRCP_current_while_timer (Short Timeout).

Once the timer expires, the flow goes to reference 3352, where the nodegoes to a defaulted state. In one embodiment, in the defaulted state,the node sets default parameter values for the neighbor node on the IPPto be the current operational parameters of the neighbor node providedby an administrator of the portal through a function such asrecordDefaultDRCPDU discussed herein above. Also, the default stateincludes report the status to management through a function such asreportToManagement discussed herein above.

At reference 3307, the node receives a DRCPDU at reference 3307. TheDRCPDU contains the PDU structure illustrated in FIG. 5, where the PDUstructure has TLVs such as the ones listed in Table 4. The PDU structurecontains home port information TLV and DRCP state TLV. In oneembodiment, the receipt of the DRCPDU is indicated in a messagegenerated by the DRCP control parser/multiplexer as a result of thereception of the DRCPDU such as DRCPCtrolMuxN:M_UNITDATA.indication(DRCPDU).

Then the node determines that the received DRCPDU is associated with theportal at reference 3308. In one embodiment, the determination includeschecking a variable (e.g., Differ_Portal as discussed herein above) thatindicating the receiving DRCPDU being associated with the portal or not.In one embodiment, the determination includes executing a function(e.g., recordPortalValues) that records portal parameter values carriedin the received DRCPDU as the corresponding current operationalparameter values for the neighbor node on the IPP. Portal parametervalues, as discussed herein above in definition of recordPortaValues,includes aggregator priority (e.g. Drni_Aggregator_Prioirty), aggregatorID (e.g., Drni_Aggregator_ID), neighbor portal priority(Drni_Portal_Priority), and portal address (e.g., Drni_Portal_Addr) inone embodiment.

If the received DRCPDU is not associated with the portal, the node mayoptionally report the status to management through a function such asreportToManagement discussed herein above. If later the node receivesanother DRCPDU, the flow goes back to reference 3308 to determine theassociation again. Similarly, when the node is at the default state atreference 3352 and it receives a DRCPDU, the flow goes to reference 3308for determining the association.

After determining the received DRCPDU is associated with the portal, theflow goes to reference 3310, where the node determines that the receivedDRCPDU is compatible with the node. The determination includes thatdetermining administratively configured values associated with theportal is consistent with the received values from the DRCPDU. Thechecking includes executing a function (e.g., recordPortalConfValues)that records neighbor node's configured parameter values carried in thereceived DRCPDU as the corresponding current operational parametervalues for the neighbor node on the IPP in one embodiment. Note theconfigured parameter values in a function such as recordPortalConfValueis different from the portal parameter values such as recordPortalValue,and the different is discussed herein above in the definitions ofrecordPortalConfValues and recordPortalValues.

If the received DRCPDU is not compatible with the node, the node mayoptionally report the status to management through a function such asreportToManagement discussed herein above. If later the node receivesanother DRCPDU, the flow goes back to reference 3308 to determine theassociation again. While executing the function such asreportToManagement, the node sets another timer to expire if no DRCPDUis received and starts the timer. Once the timer expires, the flow goesback to reference 3306.

After determining the received DRCPDU is compatible with the node, thenode records the neighbor node's state information contained in thereceived DRCPDU as neighbor node's state operational variables atreference 3312. In one embodiment, a function (e.g. recordNeighborState)records the parameter values such as portal system state (e.g.,Drni_Portal_System_State) and home node operation DRCP state (e.g.,DRF_Home_Oper_DRCP_State) carried in the received DRCPDU as thecorresponding neighbor node's operational variables such asDrni_Neigbhor_State and DRF_Neighbor_Oper_DRCP_State.

Optionally, when the recorded neighbor node's state operationalvariables differ from that of the node's state operational variables,the node sets one or more triggers to notify the neighbor node atreference 3314. In one embodiment, a function (e.g., updateNTT) is usedto determine whether further protocol transmission is required asdiscussed herein above.

The method discussed herein provides an efficient way for a DRCP node toprocess information embedded in a DRCPDU received from a neighbor DRCPnode. The information is processed in stages and it is determined thatthe received DRCPDU is associated with the portal of the DRCP node andis compatible with the node before recording the neighbor node's stateinformation. In addition, a timer is inserted to prevent the node frombeing stuck in a waiting state.

DRCP Periodic Transmission Machine

The DRCP Periodic Transmission machine may implement the functionspecified in FIG. 9 with its associated parameters discussed hereinabove.

The DRCP Periodic Transmission machine establishes the desire of theHome and the Neighbor Portal Systems to exchange periodic DRCPDUs on anIPP in order to maintain a Portal, and establishes how often thoseperiodic transmissions should occur. Periodic transmissions will takeplace if either participant so wishes. Transmissions occur at a ratedetermined by the Neighbor Portal System; this rate is linked to thespeed at which the Neighbor Portal System will time out receivedinformation.

The state machine has four states. They are as follows: NO_PERIODIC(Block 902). While in this state, periodic transmissions are disabledand the stop periodic_timer function is executed. FAST_PERIODIC (Block904). While in this state, periodic transmissions are enabled at a fasttransmission rate. This state is entered from the NO_Periodic state(block 902) in response to an unconditional transition (UCT). TheFast_Periodic state can transition to the Periodic transmission (Block910) and the slow_periodic states (Block 905). A SLOW_PERIODIC state 906can be entered from the FAST_PERIODIC 904 when the long timeout isdetermined. While in this state, periodic transmissions are enabled at aslow transmission rate. If the periodic timer expires then the statetransitions to the PERIODIC_TX (Block 910). PERIODIC_TX. This is atransitory state entered on periodic_timer expiry that asserts NTT andthen exits to FAST_PERIODIC or SLOW_PERIODIC depending upon theNeighbor's DRCP_Timeout setting.

If periodic transmissions are enabled, the rate at which they take placeis determined by the value of the DRF_Neighbor_Oper_DRCP_State.Timeoutvariable. If this variable is set to Short Timeout, then the valuefast_periodic_time is used to determine the time interval betweenperiodic transmissions. Otherwise, slow_periodic_time is used todetermine the time interval.

Thus, the embodiments provide for a process comprising the steps ofinitializing in a no periodic state in which transmissions are disabled,transitioning to a fast periodic state, starting a timer for the fastperiodic time, transitioning to a slow periodic state or a periodictransmission state in response to a long time out or a neighbor havingthe fast periodic time out setting, respectively, transitioning from aslow periodic time out to a periodic transmission state in response to ashort timeout setting at the neighbor or a timer expiration, andtransitioning from the periodic transmission state to either the fastperiodic or short periodic state in response to the neighbor timeoutsetting changing to a short time out or long timeout settingrespectively.

The DRCP Periodic Transmission machine may also implement the functionspecified in FIG. 17 with its associated parameters. FIG. 17 containsdifferent terms (e.g., DRCP_periodic_timer and NTTDRCPDU, notperiodic_timer and NTT respectively as in FIG. 9), but the flows are thesame otherwise. The terms and functions of the alternate transmissionmachine in FIG. 17 are analogous to those of FIG. 9. One skilled in theart would understand that other implementations are possible consistentwith the principles and structures of the illustrated transmissionmachines.

Portal System Machine

The Portal System machine may implement the function specified in FIG.10 with its associated parameters discussed herein above. This processcan initialize to a portal system initialize state (Block 1002). ThesetDefaultPortalSystemParameters and updateKey functions are executed.In the case either the Change Portal or the ChangeDRFPorts are true theprocess transitions to the portal system update state (Block 1004). Inthe portal system update state, the ChangePortal is set to false,changeDRFPorts set to False, update DRF homestate, and updatekeyexecution. The next update is triggered when either change portal orchange DRFPorts is update to true.

Thus, the embodiments provide for a process comprising the steps ofinitializing to a portal initialization state where default portalsystem parameters are created and a key is updated, transitioning to aportal system update state in response to a ChangePortal orChangeDRFPorts variable being Boolean true, setting in a portal systemupdate state the ChangePortal variable to false, the changeDRFPortsvariable to false, executing an updateDRFHomeState, and updating thekey, and re-entering the portal system update state upon detecting aChangePortal or ChangeDRFPorts variable being true.

On initialization the Portal System's variables are set to their defaultvalues for this Portal as configured by their administrative settings.In particular, the default operational states of all Gateways,Aggregation Ports, and IPPs, in the Portal are set to FALSE. In additionbased on those default values, the Operational Key to be used by theassociated Aggregator is calculated to be the Administrative Key valueassigned to this Portal System.

Any local change on the operational state of the Portal System'sGateway, or to the distribution state of any of the attached AggregationPorts as reported by the associated Aggregator, or any change in theoperational state of the Neighbor Portal Systems, as reported by the RXstate machine, triggers a transition to the PORTAL_SYSTEM_UPDATE state.This causes the function updateDRFHomeState to re-evaluate the variableproviding the Portal System's own state (DRF_Home_State) based on theupdated local information on the operational state of the Gateway andall the Aggregation Ports on the Portal System's Aggregator. Any changein the operational state of the Portal System's Gateway is reflected tothe GatewayConversationUpdate which is used to trigger state transitionsin the ports' state machines and IPP. Similarly, any change in theoperational state of the Aggregation Ports associated with this PortalSystem's Aggregator Port is reflected to the PortConversationUpdatewhich is used to trigger state transitions in the same state machines.Finally, the updateKey function updates the operational Key, to be usedby the Portal System's Aggregator, by selecting the lowest numerical nonzero value of the set comprising the values of the administrative Keysof all active Portal Systems in the Portal.

The state machine returns to the PORTAL_SYSTEM_UPDATE state whenever theoperational state of any of the DR Function's ports changes.

The Portal System machine may also implement the function specified inFIG. 18 with its associated parameters. FIG. 18 is similar to FIG. 10except that the system executes update Portal State usingUpdatePortalState function in FIG. 18. The terms and functions of thealternate Portal System machine in FIG. 18 are analogous to those ofFIG. 10. One skilled in the art would understand that otherimplementations are possible consistent with the principles andstructures of the illustrated Portal System machines.

FIG. 34 illustrates a method for updating operational states of a nodein a distributed resilient network interconnect (DRNI) according to anembodiment of the invention. Method 3400 may be implemented on a DRCPnode (e.g., a network device) of a DRCP portal (referred to as a localportal) as a part of a DRNI such as nodes K-O of FIG. 1B and networkdevices 132 and 134 of FIG. 1C. Note optional steps are denoted as adotted box as illustrated in FIG. 34.

At reference 3402, the node initializes for link aggregation. Theinitialization includes setting variables of the node for the portal itbelongs as configured by administrative settings. The initialization isperformed by executing a function (e.g. setDefaultPortalSystemParametersin FIG. 10) in one embodiment. The function sets the node's variable toadministrative set values as enumerated in the definition ofsetDefaultPortalSystemParameters discussed herein above, which includesa system priority of the aggregator of the node (e.g.,Drni_Aggregator_Priority), a system identifier of the aggregator of thenode (e.g., Drni_Aggregator_ID), a system priority of the portal (e.g.,Drni_Portal_Priority), an identifier for the node in the portal (e.g.,DRF_Portal_System_Number), an administrative aggregator key valueassociated with the aggregator (e.g., DRF_Home_Admin_Aggregator_Key), aport algorithm used by a DR function of the node to assign frames toport conversation IDs (e.g., DRF_Home_Port_Algorithm), a gatewayalgorithm used by the DR function of the node to assign frames togateway conversation IDs (e.g., DRF_Home_Gateway_Algorithm) and etc.

At reference 3404, the node determines that an operational stateassociated with the portal is changed. The change of operational statemay be indicated by a Boolean variable that is set to true when anoperational value of the network device's view of the value of theneighbor network device's IPP activity is active. In one embodiment, avariable such as ChangePortal discussed herein above is such Booleanvariable. The change of operational state may also be indicated by aBoolean variable that is set to true when an operational state of thegateway of the node changes. The change of operational state may also beindicated by a Boolean variable that is set to true when one ofoperational states of aggregation ports of the node associated with thefirst portal changes. In one embodiment, a variable such asChangeDRFPorts discussed herein above is such Boolean variable for bothchanges of the operational states of the gateway and aggregation ports.

At reference 3406, the node may set one or more variables indicating nooperational state change associated with the portal. In one embodiment,that is performed by setting variables such as ChangePortal andChangeDRFPorts to be FALSE as illustrated in FIG. 10. The setting allowsfurther changes of operational state trigger update of ChangePortal andChangeDRFPorts so that the node may detect the change.

At reference 3408, the node updates a set of operational states of thenode for link aggregation in response to the operational state change,where the set of operational state includes an operational state of thegateway for the node. In one embodiment, the update is performed throughexecuted a function such as updateDRFHomeState discussed herein above.In one embodiment, the update also create a list of operationalaggregation ports by including only those aggregation port identifiers(ID) which is operable (e.g., the attached aggregator reports them ashaving Actor_Oper_Port_State.Distributing==TRUE (condition that excludesthe cases where the associated aggregation ports are either non operableor in an expired state, or not in the link aggregation group)).

The method provides an efficient way to synchronize operational statesof the DRCP node with neighbor DRCP node based on changes of the portalto which the DRCP node belongs.

DRNI Gateway and Aggregator Machine

The DRNI Gateway and Aggregator machine may implement the functionspecified in FIG. 11 with its associated parameters discussed hereinabove. There are two DRNI Gateway and Aggregator machines on a PortalSystem. Each one is associated with a Conversation ID type: there is onefor Gateway Conversation IDs and one for Port Conversation IDs. FIG. 11Ais the DRNI gateway process which initializes in the DRNI Gatewayinitialize state (Block 1102). In this state theInitializeDRNIGatewayConversation function is executed and theGatewayCoversationUpdate is set to FALSE and where theGatewayCoversationUpdate occurs, the process transitions to the DRNIGateway Update state (Block 1104). In the DRNI Gateway Update state(Block 1104), the process sets the GatewayConversationUpdate to false,an updatePortaState, setGatewayConversaion operation, andsetlPPGatewayUpdate are executed and an updatePortalSystemGatewayConversation is executed. The DRNI gateway update is triggered on eachoccurance of the GatewayConversation Update.

The embodiments of the process comprise the steps of initializing to aDRNI Gateway initialization state, initializing a DRNI gatewayconversation and the GatewayCoversationUpdate to FALSE, transitioning toa DRNI gateway update state upon detecting a gateway conversation updatevariable is true, setting updatePortalState, setting the IPP Gatewayupdate triggers, setting the gateway conversation update variable tofalse, setting the gateway conversation, updating a portal systemgateway conversation and re-entering the DRNI gateway update state uponthe Gateway Conversation Update variable being set to true.

FIG. 11B is the DRNI port update process. In this process the DRNI portupdate process begins in the DRNI Port initialize state (Block 1112).The initializeDRNlPortConversation function is executed and thePortCoversationUpdate is set to FALSE and the process continues inresponse to an occurance of the PortConversationUpdate, whichtransitions the state to the DRNIPortUpdate (Block 1114). In the DRNIPort Update state, the process sets the PortConversationUpdate to false,the updatePortalState, the setPortConversation, the setlPPPortUpdateoperations and the updatePortalSystemPortConversation operation areexecuted. The DRNI port update is retriggered when there is a change tothe value of the PortConversationUpdate.

The embodiments of the process comprise the steps of initializing to aDRNI port initialization state, initializing a DRNI port conversationand the PortCoversationUpdate to FALSE, transitioning to a DRNI portupdate state upon detection of the Port Conversation Update variablebeing true, setting the IPP Port update triggers, setting the PortConversation Update variable to false, setting the Port Conversation,updating the Portal System Port Conversation and re-entering the DRNIport update state in response to detecting the Port Conversation Updatevariable is true.

These state machines are responsible for configuring the GatewayConversation IDs and the Port Conversation IDs that are allowed to passthrough this DR Function's Gateway and Aggregator based on the agreedpriority rules and the operation of DRCP.

On a trigger from the PS state machine (FIG. 10) or the DRX statemachine (FIG. 8), declaring that a Gateway's operational state haschanged, the state machine enters the DRNI_GATEWAY_UPDATE state. Thiscauses the triggering parameter (GatewayConversationUpdate) to be resetto FALSE. Then the function updatePortalState will update the variableproviding the states of all Portal Systems (Drni_Portal_System_State[ ])by combining the updated DRF_Home_State with information from theoperational state of the ports on other Portal Systems as reported bythe received DRCPDUs on the Portal System's IPPs and recorded by the DRXstate machine (FIG. 8) and sets IppGatewayUpdate on every IPP on thePortal System to TRUE to trigger further updates on the IPP statemachines (FIG. 12). Subsequently the setGatewayConversation function isinvoked to identify the Portal System that is responsible for eachGateway Conversation ID based on the agreed selection priorities and theGateways operational state as known by this Portal System (based on thelocal Gateway's operational state and the Neighbor Portal Systems'declared operational state of their own Gateways carried by the latestDRCPDU received from those Neighbor Portal Systems). Finally the,Gateway Conversation ID indexed, Boolean vector will be calculated basedon the agreement between this Portal System's view on the GatewayConversation IDs that are allowed to pass through the Portal System'sGateway and all the Neighbors' view on the Gateway Conversation IDs thatare allowed to pass through this Portal System's Gateway [as declaredthrough their DRCPDUs and recorded by this Portal System's DRX statemachine (FIG. 8)]. This ensures that no Gateway Conversation ID isallowed to pass through this Portal System's Gateway unless agreementbetween all Portal Systems is reached.

The state machine is initialized having all Gateway Conversation IDsdiscarded and transits to the DRNI_GATEWAY_UPDATE state whenever thetrigger GatewayConversationUpdate is set.

The Port Conversation ID indexed Boolean vector is set through a similarstate machine operation the only difference being the priority selectionrules are based on the agreed Port Conversation IDs and the PortAlgorithm instead of the agreed Gateway Conversation IDs and the GatewayAlgorithm.

FIG. 35 illustrates a method for configuring of a set of conversationIDs for aggregator or gateway at network device in a distributedresilient network interconnect (DRNI) according to an embodiment of theinvention. Method 3500 may be implemented on a DRCP node (e.g., anetwork device) of a DRCP portal (referred to as a local portal) as apart of a DRNI such as nodes K-O of FIG. 1B and network devices 132 and134 of FIG. 1C. Note optional steps are denoted as a dotted box asillustrated in FIG. 35.

At reference 3502, the node initializes a set of conversation IDs andthe initialization includes setting entries of a Boolean vectorassociated with the set of conversation IDs to be a sequence of zeroes.The conversation IDs are gateway conversation IDs or port conversationIDs. The Boolean vector include values indicating processing the set ofconversation IDs through a gateway or an aggregator of the node, whichsets to zeros (no processing) through initialization. Note that a DRCPnode contains a single gateway and a single aggregator.

The initialization may be performed by a function such asInitializeDRNIGatewayConversation and InitializeDRNIPortConversationdiscussed herein above. The Boolean vector may beDrni_Portal_System_Gateway_Conversation orDrni_Portal_System_Port_Conversation for gateway conversation IDs andport conversation IDs respectively. In one embodiment, an indicator of aconversation ID is the Boolean value of the entry (e.g., true meansbeing passed through the gateway or distributed through the aggregator).The initialization makes all the values to be zeroes thus not pass.

At reference 3504, the node determines that distribution of the set ofconversation IDs needs to be updated. In one embodiment, making thedetermination includes checking a Boolean variable (e.g., variables suchas GatewayConversationUpdate and PortConversationUpdate discussed hereinabove for gateway conversation IDs and port conversation IDsrespectively).

At reference 3506, the node sets values of an operational vector indexedby the conversation IDs, where the operational vector lists which nodeof the portal processes each of the set of conversation IDs. In oneembodiment, the operational vector is Drni_Gateway_Converstaion andDrni_Port_Conversation for gateway conversation IDs and portconversation IDs respectively. For gateway conversation IDs, theoperational vector lists which node of the portal passes each gatewayconversation ID. For port conversation IDs, the operational vector listswhich node of the portal passes each port conversation ID.

At reference 3508, the node sets values of the Boolean vector indexed bythe conversation IDs, where the Boolean vector lists whether the singlegateway or the single aggregator of the network device is associatedwith each of the conversation IDs. The operational Boolean vector may beDrni_Portal_System_Gateway_Conversation orDrni_Portal_System_Port_Conversation for gateway conversation IDs andport conversation IDs respectively. For gateway conversation IDs, eachentry in the Boolean vector indicates whether a gateway conversation IDis allowed to pass through the single gateway of the node. For portconversation IDs, each entry in the Boolean vector indicates whether aport conversation ID is allowed to be distributed through the singleaggregator of the node.

Then optionally at reference 3510, the node updates operational statesof all nodes of the portal. In one embodiment, the update is performedby a function such as updatePortalState discussed herein above.

Also optionally at reference 3512, the node sets a variable indicatingthat the distribution of the set of conversation IDs needs to beupdated. In one embodiment, the variable is setlPPGatewayUpdate andsetlPPPortupdate (discussed herein above) for gateway conversation IDsand port conversation IDs respectively.

Thus, embodiments of the invention provide efficient ways to configureconversation IDs so that the associated conversations may be transmittedproperly in a link aggregation group containing DRNI.

DRNI IPP Machine

The DRNI IPP machine may implement the function specified in FIGS. 12A-Bwith its associated parameters discussed herein above. FIG. 12Aillustrates a state machine to update IPP gateway conversation accordingto one embodiment of the invention. The process starts at block 1202,where an IPP gateway is initialized. In this embodiment, IPP gatewayinitialization is achieved through two initialization functions. ThroughIPPGatewayUpdate=FALSE, the network device sets the IPP Gateway Updatetriggers to FALSE. Through InitializeIPPPortConversation( ) function,the network device sets conversation passes (such asIpp_Gateway_Conversation_Direction) to a sequence of zeros, indexedagain by gateway conversation ID.

After initialization, the state machine goes to block 1204, where theIPP gateway is updated. The transmission is trigger by a variablechange. The variable, IppGatewayUpdate, indicates that a per IPP gatewayconversation ID distributions need to be updated. In one embodiment,IppGatewayUpdate is a Boolean value and once the Boolean value turns toTRUE, the state machine goes to block 1204. At block 1204. it setsgateway conversation through the function setGatewayConversation. Asdiscussed herein above, the function sets DRNI gateway conversationvalue to the values computed from current administrative value of thegateway selection priority list for the distributed relay (through avariable such as aDrniConvAdminGateway[ ]) and the current DRNI portsystem state (by reading Drni_Portal_System_State[ ] in one embodiment).Also in block 1204, the network device sets IPP gateway conversationthrough function setIPPGatewayConversation( ). Additionally, the networkdevice updates IPP gateway conversation direction through functionupdateIPPGatewayConversationDirection( ), and finally the network devicereset IppGatewayUpdate to FALSE. Block 1204 repeats itself whenever agateway conversation update is needed.

Thus, the embodiments of the process comprise the steps of initializingto an IPP gateway initialization state, initializing the IPP gatewayupdate trigger to FALSE, initializing the IPP gateway conversation,transitioning to an IPP gateway update state upon detecting an IppGateway Update variable is true, setting the gateway conversation,setting an IPP gateway conversation, updating the IPP gatewayconversation direction, setting the Ipp Gateway Update variable to falseand re-entering the IPP gateway update state in response to detectingthe Gateway Conversation Update variable is true.

FIG. 12B illustrates a state machine to update IPP port conversationaccording to one embodiment of the invention. The process for updatingIPP port is analogous to the process for updating gateway conversation,thus the process in FIG. 12B is similar to FIG. 12A with functions andvariables for IPP ports are utilized for the IPP port conversationupdate.

The embodiments of this process comprise the steps of initializing to anIPP port initialization state, initializing the IPP port update triggerto FALSE, initializing a IPP port conversation, transitioning to an IPPport update state in response to detecting an IPP Port Update variableis true, setting a port conversation, setting an IPP conversation,updating an IPP port conversation pass setting the IppPortUpdatevariable to false and re-entering the IPP Port Update state in responseto detecting the PortConversationUpdate is true.

In one embodiment, these state machines are responsible for configuringthe Gateway Conversation IDs and the Port Conversation IDs that areallowed to pass through this Neighbor Portal System's IPPs based on theagreed priority rules and the operation of DRCP.

On a trigger from the DRX state machine (FIG. 8), declaring thatIppGatewayUpdate is set to TRUE, the state machine enters theIPP_GATEWAY_UPDATE state. This causes the setGatewayConversationfunction to be invoked. This will identify the Portal System that isresponsible for each Gateway Conversation ID based on the agreedselection priorities and the Gateways operational state as known by thisPortal System (based on the local Gateway's operational state and theNeighbors' declared operational state of their own Gateways carried bythe latest DRCPDU received from those Neighbors). Then thesetlPPGatewayConversation function will identify the Portal System thatis responsible for each Gateway Conversation ID based on the agreedselection priorities and the Gateways operational states as declared bythe Neighbor Portal System on this IPP (based on the Neighbor PortalSystem's Gateway operational state and the Neighbor Portal System'sdeclared operational state on their view on other Gateways in Portal,carried by the latest DRCPDU received from the Neighbor Portal System onthis IPP). Subsequently, Gateway Conversation ID indexed, Boolean vectorwill be calculated based on the agreement between this Portal System'sview on the Gateway Conversation IDs that are allowed to pass throughthe Portal System's IPP and the IPP Neighbor Portal System's view on theGateway Conversation IDs that are allowed to pass through the same IPP[as declared through their DRCPDUs and recorded by this Portal System'sDRX state machine (FIG. 8)]. This ensures that no Gateway ConversationID is allowed to pass through this IPP unless agreement between thisPortal System and its Neighbor Portal System is reached. Finally,IppGatewayUpdate is reset to FALSE.

The state machine is initialized having all Gateway Conversation IDsdiscarded and transits to the IPP_GATEWAY_UPDATE state whenever thetrigger GatewayConversationUpdate is set.

The Port Conversation ID indexed Boolean vector is set through a similarstate machine operation, the only difference being that the priorityselection rules are based on the agreed Port Conversation IDs and thePort Algorithm, instead of the agreed Gateway Conversation IDs and theGateway Algorithm.

FIG. 36 illustrates a method for configuring of a set of conversationIDs for IPP at a DRCP node in a distributed resilient networkinterconnect (DRNI) according to an embodiment of the invention. Method3600 may be implemented on a DRCP node (e.g., a network device) of aDRCP portal (referred to as a local portal) as a part of a DRNI such asnodes K-O of FIG. 1B and network devices 132 and 134 of FIG. 1C.

At reference 3602, the node initializes a set of conversation IDs andthe initialization includes setting entries of a Boolean vectorassociated with the set of conversation IDs to be a sequence of zeroes.The conversation IDs are gateway conversation IDs or port conversationIDs. The Boolean vector include values indicating processing the set ofconversation IDs through an IPP of the node.

The initialization may be performed by a function such asInitializeIPPGatewayConversation and InitializeIPPPortConversationdiscussed herein above. The Boolean vector may beIpp_Gateway_Conversation_Direction or Ipp_Port_Conversation_Passes forgateway conversation IDs and port conversation IDs respectively. In oneembodiment, a value for a conversation ID is the Boolean value of theentry. For example, a value of TRUE for a gateway conversation IDindicates that some gateway is reachable through this IPP. Theinitialization makes all the values to be zeroes thus not pass.

At reference 3604, the node determines that distribution of the set ofconversation IDs needs to be updated. In one embodiment, making thedetermination includes checking a Boolean variable. In one embodiment,the Boolean variable is IppGatewayUpdate and IppPortUpdate for gatewayconversation IDs and port conversation IDs respectively. In anotherembodiment, the Boolean variables is GatewayConversationUpdate andPortConversationUpdate for gateway conversation IDs and portconversation IDs respectively.

At reference 3606, the node sets values of a first operational vectorindexed by the conversation IDs, where the operational vector listswhich node of the portal processes each of the conversation IDs asassigned by the node. In one embodiment, the node sets the valuesthrough functions such as setGatewayConversation and setPortConversationto set the first operational vector such as Drni_Gateway_Conversationand Drni_Port_Conversation respectively. For gateway conversation IDs,Drni_Gateway_Conversation lists which node's gateway (if any) passeseach gateway conversation ID. For port conversation IDs,Drni_Port_Conversation lists which node passes each port conversationIDs.

At reference 3608, the node sets values of a second operational vectorindexed by the conversation IDs, where the operational vector listswhich node of the portal processes each of the conversation IDs asassigned by the neighbor node. In one embodiment, the node sets thevalues through functions such as setlPPGatewayConversation andsetlPPPortConversation to set the second operational vector such asIpp_Other_Gateway_Conversation andIpp_Other_Port_Conversation_Portal_System respectively. As discussedherein above, for gateway conversation IDs,Ipp_Other_Gateway_Conversation lists which node (i.e., portal system)(if any) is passing each gateway conversation ID as assigned by theneighbor node on this IPP, the neighbor node being the immediateneighbor node when the portal contains more than two nodes. Similarly,for port conversation IDs, Ipp_Other_Port_Conversation_Portal_Systemlists which node is passing each port conversation ID as assigned to bythe immediate neighbor node on this IPP.

At reference 3610, the node sets values of the Boolean vector indexed bythe conversation IDs, where the Boolean vector lists whether the IPP ofthe node is associated with each of the conversation IDs. In oneembodiment, the Boolean vector is Ipp_Gateway_Conversation_Direction forgateway conversation IDs and Ipp_Port_Conversation_Passes for portconversation IDs as discussed herein above.

Thus, similar to method 3500, embodiments of the invention here provideefficient ways to configure conversation IDs so that the associatedconversations may be transmitted properly in a link aggregation groupcontaining DRNI.

Transmit Machine

When the Transmit machine (not illustrated) creates a DRCPDU fortransmission, it may fill in the following fields with the correspondingoperational values for this IPP according to one embodiment of theinvention:

Aggregator ID and Priority.

-   Portal ID and Priority.-   Portal System Number.-   Topology State-   Operational Aggregator Key.-   Port algorithm.-   Gateway algorithm.-   Port Digest.-   Gateway Digest.-   DRCP State.-   The Operational Aggregation Ports, the Administrative Aggregator Key    and the operational Partner Aggregator Key of the Home Portal System    and any other Portal System that its ability to form a Portal has    been verified.

When the Periodic machine is in the NO_PERIODIC state, the Transmitmachine should:

-   Not transmit any DRCPDUs, and-   Set the value of NTTDRCPDU to FALSE.

When the DRCP_Enabled variable is TRUE and the NTTDRCPDU variable isTRUE, the Transmit machine may ensure that a properly formatted DRCPDUis transmitted [i.e., issue a DRCPCtrlMuxN:M_UNITDATA.Request (DRCPDU)service primitive], subject to the restriction that no more than aspecific number of LACPDUs may be transmitted in any Fast_Periodic_Timeinterval. The specific number may vary depending on implementation(e.g., ten or twenty). If NTTDRCPDU is set to TRUE when this limit is inforce, the transmission may be delayed until such a time as therestriction is no longer in force. The NTTDRCPDU variable may be set toFALSE when the Transmit machine has transmitted a DRCPDU.

If the transmission of a DRCPDU is delayed due to the above restriction,the information sent in the DRCPDU corresponds to the operational valuesfor the IPP at the time of transmission, not at the time when NTTDRCPDUwas first set to TRUE. In other words, the DRCPDU transmission model isbased upon the transmission of state information that is current at thetime an opportunity to transmit occurs, as opposed to queuing messagesfor transmission.

When the DRCP_Enabledvariable is FALSE, the Transmit machine may nottransmit any DRCPDUs and may set the value of NTTDRCPDU to FALSE.

Network/IPL Sharing Machine

The Network/IPL sharing machine may implement the functions specified inFIG. 30 with its associated parameters. There is one Network/IPL sharingmachine per IPP in a Portal System for the supported Network/IPL sharingmethod. This machine is only required when the Network/IPL sharedmethods, Network/IPL sharing by time, Network/IPL sharing by tag, orNetwork/IPL sharing by encapsulation is implemented.

The Network/IPL sharing machine, which corresponds to method 3100 ofFIG. 31 discussed herein below, enables transmission and manipulation ofthe frames sent on the shared Network/IPL link only if the DRCPDUsreceived on the same port report the same Network/IPL sharingconfiguration by the Neighbor Portal System, thereby resulting inmultiple IPL and network link sharing a same physical link or linkaggregation.

The state machine has three states. They are as follows:

NO_MANIPULATED_FRAMES_SENT. While in this state, the IPL can only besupported by a physical or Aggregation Link.

TIME_SHARED_METHOD. While in this state, the Network/IPL sharing by timemethods specified herein above are enabled.

MANIPULATED_FRAMES_SENT. While in this state, the tag manipulationmethods of Network/IPL sharing by tag or Network/IPL sharing byencapsulation, as dictated by the Network/IPL sharing method selectedthe aDrniEncapsulationMethod, are enabled.

The System is initialized in the NO_MANIPULATED_FRAMES_SENT and IPLframes are sent on the dedicated physical link. If the Home PortalSystem is configured for Network/IPL sharing by time mode of operation,indicated by a value of 1 in aDrniEncapsulationMethod, the system willtransit to TIME_SHARED_METHOD if the DRX state machine (DRX—FIG. 8) setsCC_Time_Shared to TRUE (indicating that the Neighbor Portal System onthis IPP has also been configured for the Network/IPL sharing by timemode of operation). The System remains in the TIME_SHARED_METHOD stateuntil a received DRCPDU sets CC_Time_Shared to FALSE, which triggers astate transition to the NO_MANIPULATED_FRAMES_SENT state and IPL framesare sent on the dedicated physical link.

Similarly, if the Home Portal System is configured for Network/IPLsharing by tag or Network/IPL sharing by encapsulation mode ofoperation, as indicated by the value in aDrniEncapsulationMethod, thesystem will transit to MANIPULATED_FRAMES_SENT if the DRX state machine(DRX—FIG. 8) sets CC_EncTag_Shared to TRUE (indicating that the NeighborPortal System on this IPP has also been configured for the Network/IPLsharing by tag or Network/IPL sharing by encapsulation mode of operationrespectively). The System remains in the MANIPULATED_FRAMES_SENT stateuntil a received DRCPDU sets CC_EncTag_Shared to FALSE, which triggers astate transition to the NO_MANIPULATED_FRAMES_SENT state and IPL framesare sent on the dedicated physical link.

FIG. 31 illustrates a method for Network/IPL sharing at a node accordingto an embodiment of the invention. Method 3100 may be implemented on aDRCP node (also referred to as a portal system of a portal, e.g., anetwork device) of a DRCP portal (referred to as a local portal) as apart of a DRNI such as nodes K-O of FIG. 1B and network devices 132 and134 of FIG. 1C. Note optional step is denoted as a dotted box asillustrated in FIG. 31.

In reference 3102 a DRCP node (a local portal system) is in a normalstate of operation and IPL frames are transmitted over a dedicatedphysical link or aggregation link towards a neighbor DRCP node (aneighbor portal system). In reference 3104 it is determined whether thenode is configured in consistency with the neighbor node. For example,this may be performed using a parameter recording function, such asrecordNeighborState, that at least records the parameter value carriedin a TLV used for Network/IPL sharing from the neighbor node, e.g. fieldDRF_Home_Network/IPL_sharing_method in Table 6. The recorded parametervalue may then be compared to the current corresponding parameter valueused by the node. In case Network/IPL sharing is implemented in the nodeand in case parameter values are consistently configured in the nodes,the method proceeds to reference 3106 in which frames are transmittedfrom the node to the neighbor node using Network/IPL sharing.

Optionally the node continues using the consistent Network/IPL sharingmethod until it detects a change of Network/IPL sharing at the neighbornode at reference 3108. For example, a CC_Time_Shared orCC_Enctag_Shared indicates whether the home/neighbor nodes useconsistent sharing methods. When the two nodes do not use consistentsharing method, the flow returns to reference 3102, where the dedicatedlink or aggregation link is used.

The embodiments of the invention provides an efficient way to supportnetwork and inter-port link sharing in a link aggregation group so thatan inter-port link may share a physical link with other inter-port linksor network links.

Coordination Between DRCP and LACP Statuses: A First Set of Embodiments

In a DRNI portal system as illustrated in FIGS. 1B-1C, DRCP and LACPstatus should be consistent for the system to work properly. In FIG. 1C,the consistency is easier to maintain. Referring to FIG. 1C, the linkbetween network device 130 and network device 134 is the working link(link 172) and the link between network device 130 and network device132 is the protection link (link 174) for a service. An IPL link (notshown) between network devices 134 and 132 keeps their DRCP status insynchronization. From the point of view of network device 130 (portal142 with a single node), it is connected to a single system (portal 144)and no information regarding network devices 132 or 134 individually isexplicitly communicated to network device 130.

When the IPL link between network devices 132 and 134 goes down, bothnetwork devices 134 (currently working node) and 132 (currentlyprotection node) try to take over as the node transmitting traffic—fromtheir respective perspective, it is the neighboring node that is notoperating properly. Network device 132, as a protection node, willupdate its LAG identifier (ID) in order to avoid having the situationwhere both links 130-132 and 130-134 (links 172 and 174 respectively)carry duplicate traffic. At portal 142, the determination of which linkis to remain in a link aggregation group (i.e., working link) is basedon a decision by network device 130, which applies normal linkaggregation operations to make the choice. Particularly, network device130 puts the link 130-132 on hold to check if the link 130-134 is stillin the link aggregation group (i.e. working link carrying traffic). Ifthe link 130-134 is not in the link aggregation group, it enablestraffic on the link 130-132. When the IPL link between network devices134 and 132 is up again, the DRCP status is updated and the link 130-132remains blocked, and the LACP status keep the link 130-134 be theworking link throughout the process (thus no traffic outage).

For a DRCP system with each portal containing more than one networkdevices, maintaining consistency between DRCP and LACP status takes moreeffort. Additional information needs to be exchanged between portals andnodes to keep the portals synchronized. In particular, at least twooperation keys (one for each operational partner portal system) may beintroduced to coordinate the synchronization. One is an operationpartner aggregator key. The operation partner aggregator key isassociated with a node's aggregation link aggregation group identifier(LAG ID) (the node being a partner node). The operation partneraggregator key is transmitted in DRCPDUs. In one embodiment, theoperation partner aggregator key is stored in a variable named asDRF_Home_Oper_Partner_Aggregator_Key, which is defined as an operationpartner aggregator key associated with LAG ID of a network device (nodeof a portal) discussed herein above. The other is an operation key foreach of the partner portal systems in the partner portal. The operationneighbor's portal key are also associated with a node's LAG ID (the nodebeing a neighbor node). The operation neighbors (immediate or remoteneighbors) portal keys are transmitted in DRCPDU. In one embodiment, theoperation neighbor aggregator key is stored in a variable namedDRF_Neigbhor_Oper_Partner_Aggregator_Key(DRF_Other_Neigbhor_Oper_Partner_Aggregator_Key in the case of a thirdportal system), which is defined as the last received operation partneraggregator key value of a neighbor node (or other neighbor in the caseof a third portal system) on its associated intra-portal port (IPP).

For the aggregator keys to be exchanged, the DRCPDU may add a new fieldto hold a partner operation key, such field be used to carryDRF_Home_Oper_Partner_Aggregator_Key of one node in the DRCPDU. Afunction to record neighbor node's configured parameter value carried ina received DRCPDU from an IPP may also be updated. Such function, suchas recordNeighborState discussed herein above, may be used to setreceived operation partner aggregator key to be the last known operationneighbor aggregator key (e.g., settingDRF_Neigbhor_Oper_Partner_Aggregator_Key equal to receivedDRF_Home_Oper_Partner_Aggregator_Key). Note when a portal contains morethan two nodes, there are multipleDRF_Neigbhor_Oper_Partner_Aggregator_Key or potentiallyDRF_Other_Neigbhor_Oper_Partner_Aggregator_Key saved, one for eachneighbor node.

Referring to FIG. 1B, the link K-M is the working link and the link L-Ois the protection link. An IPL link each exists between nodes K and L,and M and O to keep their DRCP status in synchronization.

When the IPL link between network nodes M and O goes down, both nodes M(currently working node) and O (currently protection node) for a servicetry to take over as the node transmitting traffic—from their respectiveperspective, it is the neighboring node that is not operating. Node O,as a protection node, will update its LAG identifier (ID) in order toavoid having the situation where both links K-M and L-O carry duplicatetraffic. At portal 112, nodes K and L need to independently makedecisions on whether to discard or allow traffic on links K-M and L-O.The decision may be made through exchanging DRCPDUs between neighbornodes in one embodiment. In addition, the selection logic applied byeach node may be modified in order to take the exchanged informationinto account. Nodes K and L may be updated to allow traffic to passthrough its associated links K-M and L-O respectively only when itsoperation partner aggregator key is the lowest value of a set of valuesincluding its operation partner aggregator key and its operationneighbor portal key(s). For the selection to work, node O as aprotection node may update its operation key value (in one embodiment,the operation key value is updated using an update function such asupdateKey function discussed hereinabove) when it updates its LAG ID.

FIG. 19 illustrates a DRCP node's operations upon losing communicationwith its neighbor node according to one embodiment of the invention. Themethod may be implemented at any DRCP node coupled to one or moreneighboring nodes. At 1902, the DRCP node determines that it is nolonger in communication with its neighboring node(s). The loss ofcommunication may be due to IPP being disabled or malfunction, or theneighboring node being disabled or malfunction. At 1904, the DRCP nodethen determines that it is a node currently not carrying traffic. Note aDRCP node may act as working or protection node of a portal for aservice. If the DRCP node is a working node, no further action isrequired, it will continue carrying active traffic. If the DRCP node isa protection node, the method continues to 1906, where the DRCP nodeupdates its operation key and carries the active traffic. The updatedoperation key is set to the lowest numerical non zero value of the setcomprising the values of a key of this node (e.g., theAdmin_Aggregator_Key of this node), a key of the neighboring node (e.g.,the_Admin_Aggregator_Key of the neighboring node), and a key of theother neighboring node (e.g. the Admin_Aggregator_Key of the otherneighboring node) (when the portal contains 3 portal systems), on eachIPP. The updated operation key is sent over to its partner node.

According to embodiments, it is thus provided a method performed by anetwork device in a portal comprising a plurality of network devices,i.e. the network device being coupled to at least one neighbor networkdevice. The method comprises determining that the network device haslost communication with one or more neighbor network devices. Thenetwork device then determines that it is not carrying traffic over alink aggregation group to a partner network device, i.e. that it isacting as a protection node. After determining that the network deviceis a protection node, the network device updates its operation key andstarts to carry traffic over the link aggregation group.

FIG. 20 illustrates a DRCP node's operation in coordinating with itsneighbor node upon receiving multiple traffic streams according to oneembodiment of the invention. The method may be implemented at any DRCPnode coupled to one or more neighboring nodes. At 2002, the DRCP nodedetermines that it receives traffic from its partner. The partner may bea portal containing multiple nodes or a single node. The DRCP node maybe a single node of the portal, in which case, the DRCP node appliesnormal link aggregation operations to make the choice of selecting whichtraffic to allow passing if it receives multiple traffic from itspartner (e.g., allowing passing traffic on the current working linkafter determining the link and corresponding aggregation port is stillin the link aggregation group while enabling traffic on the currentprotection link after determining the working link is no longer in thelink aggregation group). On the other hand, at 2004, the DRCP nodedetermines that it is coupled to at least one neighbor node. When theDRCP node is coupled to at least one neighbor node, the DRCP node allowspassing traffic from its partner node only when the received partneroperation key is the lowest of the partner operation keys of allneighboring nodes of the portal. In one embodiment, that is to determinethat the node's DRF_Home_Oper_Partner_Aggregator_Key is lower than allDRF_Neighbor_Oper_Partner_Aggregator_Keys of the portal.

According to embodiments, it is thus provided a method performed by anetwork device. The method comprises determining that the network devicereceives traffic from a partner network device over a link aggregationgroup. The method further comprises determining that the network deviceis coupled to at least one neighbor network device, the network deviceand the at least one neighbor network device being part of a portal. Themethod further comprises receiving an operation key of the partnernetwork device and determining whether to allow traffic from the partnernetwork device based on a comparison of the operation key of the partnernetwork device and operation keys of the network devices of the portal.This may be performed by determining that the operation key of thepartner network device is lower than the operation keys of the networkdevices of the portal.

FIG. 27 illustrates a DRCP node's operation in coordinating with itsneighbor node upon a communication failure condition to one embodimentof the invention. Method 2800 may be implemented on a DRCP node (e.g., anetwork device) of a DRCP portal (referred to as a local portal) as apart of a DRNI such as nodes K-O of FIG. 1B and network devices 132 and134 of FIG. 1C, where the node is coupled to one or more neighboringnodes. At 2702, the DRCP node determines that it receives traffic fromits partner. The partner may be a portal containing multiple nodes or asingle node. The DRCP node may be a single node of the portal, in whichcase, the DRCP node applies normal link aggregation operations to makethe choice of selecting which traffic to allow passing if it receivesmultiple traffic from its partner (e.g., allowing passing traffic on thecurrent working link after determining the link and correspondingaggregation port is still in the link aggregation group while enablingtraffic on the current protection link after determining the workinglink is no longer in the link aggregation group). On the other hand, at2704, the DRCP node determines that it is coupled to at least oneneighbor node.

At 2706, the DRCP node determines whether the received operation key hasbeen updated. In one embodiment, the update is due to afailed/malfunctioning IPL. The DRCP node can determine that the partnersystem is experiencing the failed/malfunctioning IPL if the mostsignificant two bits of the received Partner_Oper_Key are equal to thevalue 2 or 3 and the two least significant bits of the AggregationPort's Partner_Oper_Port_Priority are equal to the value 2 or 3.

At 2708, the DRCP node determines whether or not it is isolated from itsneighboring node(s) of the same portal. The DRCP node may be isolatedfrom its neighboring node(s) because of failed/malfunctioning IPL. Inthat case, the DRCP node determines that the IPL communications at localand remote portals are both failed.

At 2710, the DRCP node determines whether it is within the higherpriority portal system and it acts to prevent duplicated traffic if itis. In one embodiment, the DRCP node determines whether it has thehigher priority portal system identifier than its partner portal (e.g.,at FIG. 1B, portal 112 may be the higher priority portal than portal114, in which case it performs 2710), and it drops received traffic ifit has the higher portal system identifier

According to embodiments is thus provided a method performed by anetwork device. The method comprises determining that the network devicereceives traffic from a partner network device over a link aggregationgroup. The method further comprises determining that the network deviceis coupled to at least one neighbor network device, the network deviceand the at least one neighbor network device being part of a portalcoupled to at least one neighbor node. The method further comprises thenetwork device determine whether the received operation key has beenupdated, and it determines whether or not it is isolated from itsneighboring node(s) of the same portal. The method further comprises thenetwork device drops received traffic if it has the higher portal systemidentifier than its partner portal. The embodiments of the inventionthus provides an efficient way to coordinate statuses of the neighboringnodes and partner nodes so that no duplicated traffic disrupts trafficreception in the link aggregation group implementing DRCP.

Coordination Between DRCP and LACP Statuses: A Second Set of Embodiments

For coordinating between DRCP and LACP status, an alternative way is toupdate some existing functions/variables and operates differently ifboth local and partner DRCP node can communicate its IPL status.

FIG. 26A illustrates a conversation mask TLV for an aggregation portaccording to one embodiment of the invention. Note the conversation maskTLV is the same as illustrated in FIG. 4A of U.S. patent applicationSer. No. 14/135,556, which is incorporated by reference in its entiretyas stated herein. FIG. 26B illustrates a conversation mask state fieldwithin a conversation mask TLV of an aggregation port according to oneembodiment of the invention. FIG. 26B is different from FIG. 4B of U.S.patent application Ser. No. 14/135,556 in that one field, PSI (portalstate isolated) at reference 2611 replaces a reserved bit. This flag isonly applicable for Portal Systems and is used to indicate if the PortalSystem is isolated from the other Portal Systems within the Portal ().TRUE (encoded as a 1) ifDRF_Neighbor_Oper_DRCP_State.IPP_Activity==FALSE on all IPPs on thisPortal System. Its value is otherwise FALSE (encoded as a 0).

In addition, the ReceivedConversationMaskTLV function disclosed in U.S.patent application Ser. No. 14/135,556 may be updated with the followingadditional operation: it also records the parameter value for the PSIcarried in a received Port Conversation Mask as the current operationalparameter values for the Partner_PSI.

Furthermore, the upddateConversationMaskTLV function disclosed in U.S.patent application Ser. No. 14/135,556 may be updated with the followingadditional operation: If this function is implemented by a DRCP PortalSystem, with its DRF_Portal_System_Number value set to a value that isdifferent than 1, its Portal's System Identifier set to a value that isnumerically lower than the Partner's System Identifier, andPSI==Partner_PSI==TRUE, then Comp_Oper_Conversation_Mask is set to NULL.

For example, referring to FIG. 1B, when both IPLs at K/L and M/O fail,all nodes would transmit traffic—the active nodes K and M transmittraffic as they are active nodes, and the protection nodes L and M alsotransmit traffic as they are isolated from active nodes and now considerthemselves to be active. When PSI is supported at both portals 112 and114, the PSI and received partner PSI would be TRUE. Assuming portal 112is a higher priority portal (e.g., Portal 112's System Identifier islower than Portal 114's thus its priority is higher), then node Ldetermines that its portal system number (assuming to be 2 as it's atwo-node portal, and the working node K has portal system number 1) isnot the lowest, it will update its operation conversation mask to null,and it does not transmit or receive traffic.

FIG. 28 illustrates a DRCP node's operation upon a communication failureaccording to one embodiment of the invention. Method 2800 may beimplemented on a DRCP node (e.g., a network device) of a DRCP portal(referred to as a local portal) as a part of a DRNI such as nodes K-O ofFIG. 1B and network devices 132 and 134 of FIG. 1C. At 2802, the DRCPnode determines that it is no longer in communication with itsneighboring node(s). The loss of communication may be due to IPP beingdisabled or malfunction, or the neighboring node being disabled ormalfunction. The loss of communication may be indicated in the PSI bitbeing set to be TRUE (which is sent through a TLV in a LACPDU discussedherein above) in one embodiment.

At 2804, the node determines that its partner node is no longer incommunication with the partner's neighboring node. The partner node maysend over its PSI status via its LACPDU and the PSI will be recorded bythe partner's recordReceivedConversationMaskTLV function. When thepartner node is no longer in communication with its neighboring node,the received PSI status will be set to TRUE, in which casePSI==Partner_PSI==TRUE.

At 2806, the node determines that its portal is a higher priority portalthan that of its partner node. The portal being a higher priority portalmay be determined based on the protal's system identifiers of the nodeand the partner node in one embodiment.

At 2808, the node determines that it is not the highest priority node ofits portal. The priority of the node within its portal may be determinedby its portal system number, which is between 1 to 3 in one embodiment(for a portal of up to 3 nodes). The node determines that it is not thehighest priority node of its portal if its portal system number is not 1in one embodiment.

At 2810, the node stops transmitting and receiving traffic of the linkaggregation group. In one embodiment, the node sets itsComp_Oper_Conversation_Mask, which is the operational value of thenode's operation conversation mask computed by an update conversationmask function (e.g., updateConversationMask).

According to the embodiments, it is thus provided a method performed bya network device in a portal comprising a plurality of network devices,i.e. the network device being coupled to at least one neighbor networkdevice. The method comprises determining that its partner node is nolonger in communication with the partner's neighboring node. The networkdevice then determines that its portal is a higher priority portal thanthat of its partner node. The network device then determines that it isnot the highest priority node of its portal, and it stops transmittingand receiving traffic upon the determination. The embodiments of theinvention thus provide an efficient way to coordinate statuses of theneighboring nodes and partner nodes so that no duplicated trafficdisrupts traffic reception in the link aggregation group containingDRCP.

Embodiment of Network Devices

FIG. 13 is a diagram of one example embodiment of a network device toexecute DRNI functionality described herein. The network device 1380 canbe a router or similar device implementing a link aggregation sublayer1370 as described herein above in regard to FIG. 2 and supports the linkaggregation functions described herein above. The network device 1380can include a network processor 1300, a set of ports 1340, a storagedevice 1350 and similar network device components. The components of thenetwork device are provided by way of example and not limitation. Thenetwork device 1380 can implement the aggregation functions and the linkaggregation sublayer 1370 using any number or type of processors andwith any configuration. In other embodiments, the aggregation functionsand link aggregation sublayer and related components are distributedover a set of network processors, a set of line cards and theirconstituent general purpose and application specific processor orsimilar implemented in a network device architecture.

The ports 1340 can connect the network device via a physical medium suchas Ethernet, fiber optic, or similar medium with any number of othernetwork devices. Any number and variety of ports can be present in thenetwork device 1380. Any combination or subset of the ports 1340 can beorganized and managed as a Link Aggregation Group or a DRNI Portal wherethe network device functions as an Aggregation System. Thus, ports canbe aggregation ports for one or more link aggregation groups.

A set of storage devices 1350 within the network device 1380 can be anytype of memory devices, caches, registers or similar storage devices foruse as working memory and or persistent storage. Any number and varietyof storage devices 1350 can be utilized to store the data of the networkdevice including programmed data and received data traffic to beprocessed by the network device 1380. In one embodiment, DRNI datastructures or similar organization of the conversation service mappingdigest, conversation masks, and similar data structures described hereinabove can be stored in such a data structure. Other data structuresstored in the storage device 1350 can include those described hereinabove. In other embodiments, these data structures can be conceived asbeing independent and can be distributed over any number of separatestorage devices 1350 within the network device 1380.

A set of network processors 1300 can implement the aggregation and DRNIfunctions and the link aggregation sublayer 1370 described herein above.The aggregation functions can include aggregator client(s) 1372 and theLink Aggregation Sublayer 1370, which can include controlparser/multiplexer 1302, aggregation controller 1306, frame collector1325, frame distributor 1320, and DRNI 1313.

The aggregation controller 1306 as described further herein above, canimplement link aggregation control and the link aggregation controlprotocol functions. These functions manage the configuration andallocation of link aggregation groups, the DRNI Portal and similaraspects. The control parser and multiplexer 1302 identifies and forwardsLACPDUs from the other data traffic received on the aggregation portsand sends the LACPDUs to the aggregation controller 1306 and other datatraffic within the link aggregation sublayer 1370.

The link aggregation sublayer 1370 as described further herein above,manages the collection and distribution of the frames according thedistribution algorithm. Within the link aggregation sublayer 1370, framecollector 1325 receives the frames and organizes them according to thedistribution algorithm shared with the partner system across the linkaggregation group. A frame distributor 1320 prepares and selects theoutbound frames for transmission over a set of aggregation portsaccording to the distribution algorithm. A client interface receives andtransmits frames to and from the aggregator client(s) 1372. Inboundframes are passed from the fame collector 1325 to the aggregatorclient(s) 1372 and outbound frames are passed from the frame distributor1320 to the aggregator client(s) 1372. The DRNI functions 1311 describedherein above are executed by the network processor 1311.

While the invention has been described in terms of several exampleembodiments, those skilled in the art will recognize that the inventionis not limited to the embodiments described, can be practiced withmodification and alteration within the spirit and scope of the appendedclaims. The description is thus to be regarded as illustrative insteadof limiting.

1. (canceled)
 2. A method supporting a link aggregation group at anetwork device, wherein the network device and a neighbor network deviceare included in the link aggregation group, wherein the network deviceis coupled to the neighbor network device via a port, the methodcomprising: encapsulating a protocol data unit in a frame, wherein theprotocol data unit includes: a type field indicating a type of theprotocol data unit, a version field indicating a protocol version numbercorresponding to the protocol data unit, an aggregator priority fieldindicating a priority corresponding to an aggregator of the networkdevice, an aggregator field indicating a value corresponding to theaggregator, an aggregator key field indicating an aggregator key valueof the aggregator, a neighbor type/length/value (TLV) indicating aneighbor information field, and a terminator TLV indicating an end ofthe protocol data unit; and transmitting the frame encapsulating theprotocol data unit from the network device to the neighbor networkdevice via the port.
 3. The method of claim 2, wherein the valuecorresponding to the aggregator is to identify an actor system.
 4. Themethod of claim 2, wherein the terminator TLV includes a TLV type fieldindicating a value of zero.
 5. The method of claim 2, wherein theprotocol data unit further includes a terminator length field, andwherein a value of the terminator length field indicates a value ofzero.
 6. The method of claim 2, wherein the protocol data unit furtherincludes a field indicating a value for the port.
 7. The method of claim2, wherein the protocol data unit further includes an organizationspecific TLV that indicates a TLV type, an organization specific length,an identifier, and a subtype.
 8. The method of claim 2, wherein theprotocol data unit further includes a flag indicating whether a receivemachine for the link aggregation group is in an expired state.
 9. Anetwork device to support a link aggregation group, wherein the networkdevice and a neighbor network device are to be included in the linkaggregation group, wherein the network device is to be coupled to theneighbor network device via a port, the network device comprising: portscoupled to one or more physical or aggregation links of the linkaggregation group; and a processor coupled to the ports, operative tocause transmission of a frame encapsulating a protocol data unit fromthe network device to the neighbor network device via the port, whereinthe protocol data unit includes: a type field indicating a type of theprotocol data unit, a version field indicating a protocol version numbercorresponding to the protocol data unit, an aggregator priority fieldindicating a priority corresponding to an aggregator of the networkdevice, an aggregator field indicating a value corresponding to theaggregator, an aggregator key field indicating an aggregator key valueof the aggregator, a neighbor type/length/value (TLV) indicating aneighbor information field, and a terminator TLV indicating an end ofthe protocol data unit.
 10. The network device of claim 9, wherein thevalue corresponding to the aggregator is to identify an actor system.11. The network device of claim 9, wherein the terminator TLV includes aTLV type field indicating a value of zero.
 12. The network device ofclaim 9, wherein the protocol data unit further includes a terminatorlength field, and wherein a value of the terminator length fieldindicates a value of zero.
 13. The network device of claim 9, whereinthe protocol data unit further includes a field indicating a value forthe port.
 14. The network device of claim 9, wherein the protocol dataunit further includes an organization specific TLV that indicates a TLVtype, an organization specific length, an identifier, and a subtype. 15.The network device of claim 9, wherein the protocol data unit furtherincludes a flag indicating whether a receive machine for the linkaggregation group is in an expired state.
 16. A non-transitorymachine-readable storage medium having instructions stored therein,which when executed by a processor, are capable of causing the processorto perform operations in a network device of a link aggregation group,wherein the network device and a neighbor network device are included inthe link aggregation group, and wherein the network device is coupled tothe neighbor network device via a port, and the operations comprising:encapsulating a protocol data unit in a frame, wherein the protocol dataunit includes: a type field indicating a type of the protocol data unit,a version field indicating a protocol version number corresponding tothe protocol data unit, an aggregator priority field indicating apriority corresponding to an aggregator of the network device, anaggregator field indicating a value corresponding to the aggregator, anaggregator key field indicating an aggregator key value of theaggregator, a neighbor type/length/value (TLV) indicating a neighborinformation field, and a terminator TLV indicating an end of theprotocol data unit; and transmitting the frame encapsulating theprotocol data unit from the network device to the neighbor networkdevice via the port.
 17. The non-transitory machine-readable storagemedium of claim 16, wherein the value corresponding to the aggregator isto identify an actor system.
 18. The non-transitory machine-readablestorage medium of claim 16, wherein the protocol data unit furtherincludes a field indicating a value for the port.
 19. The non-transitorymachine-readable storage medium of claim 16, wherein the protocol dataunit further includes an organization specific TLV that indicates a TLVtype, an organization specific length, an identifier, and a subtype. 20.The non-transitory machine-readable storage medium of claim 16, whereinthe protocol data unit further includes a flag indicating whether areceive machine for the link aggregation group is in an expired state.21. A network device to support a link aggregation group, wherein thenetwork device and a neighbor network device are to be included in thelink aggregation group, and wherein the network device is to be coupledto the neighbor network device via a port, the network devicecomprising: ports coupled to physical or aggregation link of the linkaggregation group, wherein the ports include aggregation ports; and aprocessor coupled to the ports, the processor to be operative to: enteran expired state at the network device upon a determination thatdistributed resilient control protocol (DRCP) is enable at the port,wherein the network device sets a DRCP state parameter of the networkdevice to expired, and upon receiving a protocol data unit beforeexpiration of a timer, wherein the protocol data unit includes neighbornetwork device's state information, determine, if it was determined thatthe received protocol data unit is associated with a portal, that thereceived protocol data unit is compatible with the network device,wherein the determination comprises determining that administrativelyconfigured values associated with the portal are consistent with that ofthe received protocol data unit, and record, if it was determined thatthe received protocol data unit is compatible with the network device,neighbor network device's state information included in the receivedprotocol data unit as state operational variables of the neighbornetwork device at the network device, wherein the neighbor networkdevice's state information includes protocol data unit variables for theport.